Sorry I don't do 125s but my 100 Slicks are exactly 1" long from tip to arrow. Since the weight increase is all in the shank, I'm (guessing) the 125 are not much longer than 1.25". One thing is different between the two. The Sllck has 4 blades whereas the Nitron has 3. IMO the extra cutting surface is good for terminal performance, i.e. more hemorrhage from bigger entry/exit holes. Then too I've found small, 4 bladed heads to give me most consistent accuracy from one arrow to the next.
Got to admit they look good. But given the 100% hit/kill ratio I've got going with Slicks, not likely I'll change.