Ha! That's what we're all here for, right?
I just double checked some things, and the front spring mounting bolt is 2-3/8" from the front edge of the frame. Keep in mind, if you're using an older frame, that measurement may not be exactly what you want. I can throw an angle finder on my shackles tomorrow, if you want, but again not being stock and being pretty worn out, I don't know how valuable that number will be to you.
As to spring orientation, my springs have the longer side to the front (shackle side) and the shorter side at the fixed mount. The axle is pretty centered, but has a bit of room to flex and not be way forward of center. If the longer side were to the back, the axle would be way too far forward, hitting the fender and throwing the steering linkage and sway bar mounts off.
1983 J-10 - 4.6L(MPFI)/CS130D/Hydroboost/NV3550/D300/44/44/3.54/Disc-Disc/32s/42 gallon 'burb tank