Get the gel kit. I have used the other kit and its runny. You can add stuff to stiffen it up some.

Also, don't be nervous. Just put several coats of release agent on, Even some carnuba was. I too am always nervous. Just remove the trigger assembly, put masking tape on everything. Don't be so concerned about clay dams. I usually overdo this, and makes a job turn out like crap. I myself don't worry about the tang bedding. Only the recoil lug area. Also don't be afraid to hog the crap out of the recoil lug area. In fact, go wild in that area removing material, it will fillin with stronger glass. If you don't, you can get a very thin film in the recoil lug area and it will pull up or wear when removing.

If you going with the factory tupperware stock, I highly recommend not only glass, but pillar bedding.