Project Gun

[ajw65]

I am going to put together a 20 gauge Turkey Gun. I have several questions? I plan to mount a red dot on the gun, I like ultra dots as I have several on handguns, but I could use something else. I am worried about the dots setting up to high. The guns I plan to use is a Nova with 24" barrel as I have one in my safe, or plan on purchasing an 870 with 21 in barrel. The problem with the Nova is if the sight sits to high you can't change the stock. What mount would be suggested?