You need to do what's right for your family, and I know RF vs FF for your son and the situation with your husband has been talked to death, so I'm not going to go there.
But, do not ever, EVER feel silly for being proactive and doing what's best for your kids. To be the best parent you possibly can is to fight these fights, the ones that nobody cares enough to fight for their kids, to stand up for what you feel is important. For most of us here on the board it's ERF; for some people it's nutrition, for some cloth diapering, for some the right to send their kids to daycare and go to work.
If you merely do what everyone else does, because everyone else does it, then that's what your kids learn. There are many, many fights we have to have in life and if you're going to fight them, you have to know what's important. I'm sure people think I'm insane EVERY DAY (my mom and dad certainly do) because I do what I do for the kids I watch -- spend $$ on seats, spend $$ on semi-healthy (ha) food, take six kids to the zoo or science museum or whatever -- but to be honest, I don't find there to be another option. I'm not going to do less for "my" kids because other people do less for theirs, kwim? And I want them to learn that there are some things that are worth going against the grain for.
Take pride in the fact that unlike everyone else, you're not willing to settle for "what everyone else does." You've taken the time to do your research and make an educated decision that you feel is best for your child. Don't let anyone else talk you out of what you KNOW. If your husband has concerns, he gets a say -- he's the other parent -- but don't let ANYONE else tell you what's right for YOUR kids.
Okay, off my bandwagon now. I don't mean this as a beratement... my intention is a pep talk... I hope it comes off that way. You are in the right, Mama, you are making the choice that you feel is best for your child.
(And BTW, 4-6lbs on a 2yo can take quite a while. My J was 38lbs at 2 and now, at 3.5, is just 41. He crossed both the weight and height limits for his MR RFing together, right around his third birthday.)