I like the Protektor "Doctor" model with the silver slick-top. They will make it any way you want it. MY suggestion: get a 1" thick base and MAKE SURE the space between the ears is correct for your rifle. They will build it to your exact specs. AND they will fill it and have it in your hands in 2 weeks!
I like and have this one also...one thing I would suggest and this is just me, but if I could do it over I would have got the one with the handle.
I also did add a little lead shot to the mix. I got the heavy sand but thought I needed a little more weight. I didn't quite do a 50/50 mix though...more like 75/25.