I have a new Rem 20 g 870 that I would like to set up with a FF III this year and I have some questions that may sound a little ..dumb..sorry. First off the gun will need drilled/tapped so I assume I will have to decide which base I am going to use (prob 336) and have it d/td for that base? Next what do I need with the site to mount it to this base? Thanks for any insight...I don't want to screw this up ...lol.