Jay you don't need a vice to "torque down" the scope.
You just need something to hold the gun level while you level the scope in the rings and then gently tighten the scope rings without disturbing your set up.
Some receivers are easier then others to level with a small torpedo level, and I usually level off the turret caps and when that all looks close I shoulder the rifle and aim at a known vertical line such as a door or window frame but you could also use a plum bob or laser level etc.
I don't worry about it to much as long as when I shoulder and get on the stock with a nice cheek weld the cross hairs are level and plumb.
Try youtube for some video tutorials on scope mounting.
Depending on your rings they may need to be lapped for a true pro job.
Again depending on the receiver shape you could eye ball the scope turrets with a straight edge or small square then check shouldered aiming at a vertical line.
Sounds like if anything a shooting rest might be what you are looking for, it could be used to help mount the scope and sight in but its not going to be as solid a bench mounted vise but fine for scope mounting.
A solid shooting rest might help sighting in using the 2 shot technique where you aim at the center of the target , fire, then re aim at the center if the target and adjust the turrets without moving the gun till they meet the bullet hole.
3rd shot to verify.
This assumes that you are bore sighted and on paper at your chosen range.
