The club I belong to provides simple front rests at most benches. They are made of a stack of 2x4's ~15", 10" and 5" long, giving you three different height ledges to rest the fore end upon. There's additional 15" 2x4's underneath for more elevation, but I don't recall how many (maybe just one, since they are also used for pistol rests)

With crosswise 2x4 feet under each end for stability, and old carpet on the ledges, it is simple but solid and effective with a rear bag. You could add a broad V notch in the top of each ledge to cradle the fore end a little.

I was taught to use the rear bag to fine-tune the aim point, so nothing better than gross elevation steps is fine with me.

-- Andy - Arlington TX