I prefer using vertical total 1500 or VT 1502 (whichever one works and doesn't cause strange pulse errors or stuttering) instead of VT 1350.
But to answer your question, setting the slider to the *far left* is the most compatible setting and will work with all refresh rates and custom resolutions. This will leave some crosstalk around the last 1/10th of the screen. Setting the crosstalk slider to the left corresponds to "strobe phase 000" in the service menu.
There are _some_ issues with setting the crosstalk slider to the far left that are not that critical but can be noticeable at low refresh rates.
The first is, the crosstalk at the very top of the screen is only completely 100% clear if the strobe duty is set to 001 (lowest persistence; dimmest screen) and is only unnoticeable (meaning theres no real ability to notice it outside of a testUFO full screen alien invasion test) if the strobe duty is no higher than 003. At strobe duty 003, you will see the very top of the strobe pulse start to show errors along the top few pixels of the screen, which have no effect on any real world gaming usage whatsoever, but as you raise the persistence (increases the brightness and lowers the amount of blur reduction, since strobe duty 003 is a rather dim screen), the strobe crosstalk at the top of the screen moves downwards more, and once you go past strobe duty 006 (1.0ms persistence), it actually gets large enough to be visually distracting in gameplay. There's no way to stop this from happening: raising the strobe duty lowers the crosstalk at the top of the screen and moves it downwards, but to a FAR less degree than changing the strobe phase. With the crosstalk at the far left ,I find strobe duty 006 (1.0ms persistence with a VT tweak) to be the absolute limit to what is acceptable crosstalk at the top of the screen. Any higher (even though I get a brighter picture), and it becomes annoying.
The second is that having the strobe phase at 0 ADDS one frame of input lag compared to having the strobe phase set to the maximum value (or the highest value before the backlight shuts off due to the persistence dropping to 0--this only happens if you are using a VT tweak and this changes based on the refresh rate). Masterotaku found this out a long time ago but no one believed him then, but he was right all along. This is because past a certain strobe phase, and you can test that by raising and lowering the strobe phase, on the TestUFO, alien invasion test, you will notice that the UFO's move either "ahead" or "back" one entire frame. This is the reason that the default strobe phase for a full factory reset or fresh firmware flash is 100--Benq's presets are optimized for lowest input lag, and the least crosstalk at the top of the screen (similar to Lightboost mode).
http://forums.blurbusters.com/viewtopic.php?f=13&t=560
While having a strobe phase of 000 and losing 1 frame of input lag (how much ms you lose depends on the refresh rate, of course) is probably insignificant at 120hz refresh rate, but at 50hz (using a VT of 1360 single strobe; do NOT try 50hz WITHOUT a VT tweak, ever!), a strobe phase of 000 has 20 ms (!) more input lag than strobe phase of 100. It's measurable and noticeable in call of duty advanced warfare, with vsync at 50hz.
Now, VT tweaks lower the position of the crosstalk at the -bottom- of the screen (basically, pushing it downwards; VT 1500 pushes it downwards more than VT 1350) while not affecting the position of the crosstalk at the -top-. If there is too much strobe crosstalk at the TOP of the screen (e.g. if you are using a high persistence value, for example), then you can gain 1 frame of improved input lag and make the top of the screen perfect, by raising the strobe phase. Without a VT tweak, you can go to phase 100 at all refresh rates,
With a VT tweak, the maximum strobe phase is limited by the refresh rate. Going past the maximum value will shut off the backlight until blur reduction is toggled off (basically the persistence decreases as phase increases until persistence drops to 0). Some values for maximum strobe phase (the persistence will be 0.167ms at the maximum strobe phase, or the equivalent of strobe duty 001--you will notice that if you try to raise strobe duty at the maximum strobe phase, nothing happens, right?)
125 hz: VT 1498: 047
120 hz: VT 1500= 049
100 hz: VT 1502: 059
91 hz: VT 1502: 065
85 hz: VT 1501: 70 (I think)
So, for a strobe duty of 004 (0.668 ms persistence) and for gaming at the lowest input lag, without having too much crosstalk at the bottom of the screen, and having the top of the screen perfect (this is what masterotaku likes to do), you could use:
125 hz: VT 1498, strobe phase 044 (max persistence is 0.668), strobe duty 004
120 hz: VT 1500, strobe phase 046, strobe duty 004
100hz: VT 1502: strobe phase 056, strobe duty 004,
etc.
If the screen is too dark, drop the strobe phase by 2 so you get 1.0ms persistence (maximum strobe duty will be 006 now), but this may put too much crosstalk at the bottom of the screen.
The entire reason that Chief Blur Buster's strobe utility slider is limited to 047 strobe phase for the right most slider, is to prevent a black screen when enabling blur reduction, from having the strobe phase set too high. The highest refresh rate anyone would really use a VT tweak for is 125 hz (since this matches the synchronization of 1000hz gaming mice divided by 4 evenly), and the absolute highest refresh rate that will accept VT tweaks without out of range errors is 128hz (129 hz is erratic, just like 76 hz).
IF you are gaming at 60hz refresh rate with single strobe enabled (flickery screen), you want the strobe phase at 100 or as high as possible, as strobe phase 0000 will cause an extra frame of input lag. And if you are at 60 fps, losing 1 frame of lag can be noticeable.