Tuning Tuning my Impact MKII for .30 cal FX Hybrid Slugs

I'm about to tune my FX Impact MKII with Power Plenum (700mm, .30cal, with STX Superior Liner) for the .30 cal FX Hybrids Slugs. What FPS do these .30 hybrid slugs perform best at? Given the specs of my gun, what FPS do you guys suggest I 'aim' for as a baseline for my tuning process (pun intended)?

Just trying to get an idea of where I should be at before I start tweaking everything to achieve perfect harmonic bliss and spiritual enlightenment. Thanks!
 
Coming from my personal experience using the 44.5 hybrids exclusively my FX Impact 30 Compact rifle with superior liner shoots them very well between 900-925 FPS. Pretty stable from 35 yards out further. Getting a deviation of 3-5 FPS over 17 shots. Pretty good groups at 3/4 at 50y and about 1-1.25 at 100y. I am pretty much letting 17 shots each time that that's one ragged hole. I tried the superior heavy liner and I was not getting as good of groups. I think the slug might be a little light for that heavy barrel.

I also tried the NSA 43.5 and they shot just as consistent but the groups opened up slightly at 50y and 100y. I have ready several posts with guys that are shooting the hybrids out of 700mm barrels and they are usually around 950ish, if I remember correctly.