Is the guy who prepared and served the food a part of the foodie group? Or was he hired to cook and serve? If he is a member of the group, I don't think he should be tipped. I don't think he should be looking to turn a profit and make money off of his friends. And a bottle of wine per person? I find that to be excessive and it makes him seem like he's trying to line his pockets AND his wine cellar.
The guy runs the meetup so I assume he "owns" it. His dinners all seem to be the same price, regardless of what he's serving (one recent one was a shrimp tapas "feast," which I thought might be interesting but when I looked at what he was serving -- about five shrimp appetizers -- vs. the price, I thought it too high). Also, I rarely drink but will have sips from the wine of DF on rare occasions. Two bottles of wine for us would be excessive; he wouldn't be able to drive if he drank an entire bottle himself (and the 2nd bottle of wine would be pointless for me since I wouldn't drink it). I enjoy cooking as well -- so much so that I take classes from a professional program when I can (sidenote -- a local specialty market is offering basic butchering classes, which I've been looking forward to taking all year).
With sparksals explanation about the cost of the meetup, I can understand better about wanting to recoup that cost...but $35 PLUS a bottle of wine each PLUS a gratuity still seems high to me when it's in someone's home (and I used to regularly spend about $35-40 on a nice dinner out without wine -- now I'm reluctant to pay someone else that which I can do myself). As others would say, YMMV.
I'm glad for the explanation about the wages of catering staff because I had no idea they weren't at least standard minimum per hour (not server's hourly). DF and I weren't going to hire staff for our reception, but I'm no longer wanting to handle everything myself so was thinking about hiring students from my school's program (so students who are studying to be chefs and since it's a program of which I've been a part off and on for the past four years, I know firsthand it's a good program).