I recently aqcuired a GSR gear set to put into my LS YS1 case. I got the complete assembled countershaft and partially disassembled mainshaft. I've had a few transmissions apart before for gear swaps and LSD installs and stuff, so I'm not a total noob in there. I have the mainshaft complete up to the 5th gear synchro. in the box of fun parts I got there are 2 that seem to fit here. The only obvious differences are:

1. The teeth on one are a bit taller than the other, the taller one's teeth are bigger than most of the other synchros in the tranny, but the short ones are close to all the other gears.

2. The overall width of the larger-toothed one is ~8.99mm, and the other is ~8.92mm.

3. The larger teeth are ~4.65mm flat to point, and the shorter ones are ~2.32


Which is the one to use here?