I normally shoot my STI Edge in USPSA with 4.7-4.9 grains of titegroup and an oal of 1.200. I think the gun will shoot factory length, 1.135, but I like the longer length. The gun shoots very softly and makes power factor.
I also shoot a Glock 35. They use the same amount of titegroup, but are loaded to 1.135. I could not find my chrono information, but it is my recollection that they were not too far off. The longer barrel in the STI compensates for the longer length of the ammo.
If I shot both at the same time, I would probably try the 1.135 in the STI to make it easier to load. Since I don't shoot the Glock very often, I made up a batch of "short" ammo and now load for the STI as needed for matches.
I suggest that you try long and short to see if (1) they both run through your gun; and (2) you like the feel of one better than the other.
This is why I reload. It allows variations that work for me.
Nels