An easier option to consider is to pick up a 1-oz tube of Devcon Plastic Steel for less than 5$. I find the consistancy to be perfect and the syringe allows you to dispense what you need and an accurate mix ratio..
Make sure you rough up the surface of the bedding block to get a good bite for the bedding compound. Dimpling it with a drill bit ~1/8" diam and 1/16" or so deep, or sanding with coarse paper should do.
I used Acra Glas Gel with aluminum powder to do an HS stock 20 years ago and it's still holding up fine.