My (admittedly awful) 20 yard groups were cut in half, back to back vs stock. I played with 10 yards and different combinations of the medium backstraps or none, and in all cases shot best with no backstrap and the Vickers trigger.
I went home upon putting a whole 17 mag into one hole, taking up half the inside of a Dot Torture circle, at 5 yards.
Btw my G5G17 that's always auto-forwarded, still does with the Vickers trigger.