Welcome to the site....yes definitely a good group of guys and enthusiastic bunch as well here. Good question from Nipper about having an i/o or an outboard as far as seating is concerned as the engine cover on an I/o will not allow a bench seat across the back.
This is a picture of the 1987 brochure which is a helm seat and then a back to back....I think at the time you could have got it with two helm seats though which gives you alot of floor space but obviously only 2 places to sit.
To be honest seating six in a permanently installed seats may be difficult....I guess you could go with two sets of back to back seats, passenger and helm and then a bench seat in the back or jump seats on each side of the engine cover if it is an i/o. If you do some searches you will also see alot of guys opt for the folding aluminum or ss deck chairs which have their advantages of being removable.....
If you do go back to back dont buy the standard 10" high bases that most everyone sells....especially if you do it for a helm seat....way too low on a V-20 and you wont be able to see crap....14" or 16" base is much better.
search the gallery and you will see all the different arrangements possible....post up some pics when you have some.