Please don't hold back from swinging because of your weight. Just be selective about the swing clubs you attend and the couples or singles you meet with.
Bob is heavy while I am very fit. The first time we went to a swing club it was LaTrapeze in New York City. The first couple we played with was a guy who was fairly fit, but his wife was fairly heavy. We had fun with them but I was disappointed that the wife would not let me play with her. We had lots of fun there over a long period of visits because the folks were comfortable with Bob and we had lots of play. We found out that some of the other clubs there cater to younger, fit couples and singles, so we have avoided them.
We also have gone to swing clubs in LasVegas, where we found that Red Rooster to be very accepting of us. Also, we have gone to swing clubs in the Miami area, finding acceptance and having lots of fun at Club Hedo in Pompano Beach but avoiding Miami Velvet and Trapeze, who cater to the younger, fit group.
We notice on SLS that there a lots of couples who are heavy. We have had lots of positive responses on that site and have found folks there that we have meet the played with.
So, just be selective, open, and you will find folks who find you compatible.