Weight has never been a factor in becoming friends with someone for me.
It may be a factor in how I meet that person, at well over that weight and in a wheelchair, the chances of me meeting someone rock climbing or hill walking are pretty much nil, though I do have friends who do such things.
Im interested in people who share some (not necessarily all) interests with me, who are funny, clever, kind, interesting.
I think my biggest deciding factor is liking animals - I am highly unlikely to become friends with or maintain a friendship with someone who dislikes animals or, finds it acceptable to treat animals poorly 'because they're animals'.
I haven't found being huge has ever affected my ability to make friends - sure there have been people I have met who have been arseholes in relation to my weight, which immediately means I wouldn't want to be their friend.
I have lots of friends, both close ones and the 'pop in and out of your life and pick up as if they'd never gone anywhere at all' kind. I can't recall a time, even when I was seriously depressed (and actually a lot smaller than I am now) where I was short of friends.