Typically there isn’t much to gain from 20”, but there will be some gains, if accuracy is your utmost goal and weight isn’t an issue. Keep in my mind your limitations. We don’t know you so don’t be insulted but you can build something far greater than you can reach for accuracy limits. If you have a precision rifle that can do 5 shot groups at .5 moa but you can only shoot 1.5 moa, no part in the world can fix that. I have had one day where I got .375” out of my OBR but have repeated it in YEARS! I’m typically a .75” group. I know the rifle can do it, I’ve done it, but I also know I have been getting the trigger time lately. Just food for thought.