I found this method some time ago and now have saved Hours in setting up
1) get a piece of bar that fits VERY snugly into the T slot
2) get a slot drill the same size as the bar in T slot
3) turn vice upside down and grip the piece of metal in the t slot
4) Do a slot in the base of the vice slightly deeper as the bit sticking out of the T slot ( hope this makes sense)
50 Remove vice, remove bar and place in base of the vice
6) next time you want to use the vice, just place it in the slot and it is set up
7) Job jobbed