One needs to ask themselves what is the purpose of a paid section. Raise money to help cover hosting fees? Be the dividing line between casual members and regular members?
I belong to other forums non fishing related. some offer a paid membership option. I agree with you can not tie membership payment to content. you will lose people and divide the forum.
You can tie fees to features though. increased inbox size, badges, signatures, skins and the like.
There are ways to fund the forum through sponsorship. The forum I ran generated about 10K a year through sponsorship. Members never paid a dime though. Mods did not make money either.
As for raffles. There are tons of ways to manage this without fees. One forum a mod/admin takes donations from members in the form of product and each month makes 2-3 starter kits from the donations and does a contest. Another forum does a PIF type thing. Going to try the PIF here to see if there is interest.
The site works, before I say what I think about paid memberships I would need to know why,