I think how comfortable or uncomfortable someone is on a ride varies by person and by the ride,physically and mentally we're all different.I had no problem on FoP,I'm pretty average size and just hopped on the seat which feels like you're on a motorcycle,I felt something hit my lower back and my legs a little bit but overall I was comfortable with no claustrophobia issues.Mission Space is a ride I used to ride often when new but today I rarely if ever ride it,at a certain point the ride started getting boring for me and I do get a tad claustrophobic in it.I've also found some rides where my legs get restrained or I can't move them much I have to start thinking happy thoughts or risk freaking out,once the ride gets going I'm fine but if I sit there at the loading/unloading for too long or god forbid the ride stops and I'm in there sitting for an extended time,who knows how I'll react.I've heard others say their issue is the upper body,the opposite of my issue,for me as long as I can kick my legs around or move them I'm good.In FoP I think just being in that position straddling the seat like on a bike takes away from issues,it just puts you on a mind frame like you're going to ride off somewhere and once the ride starts it feels so realistic like you're flying I can't imagine having claustrophobia issue.Physically I don't know just how comfortable or uncomfortable a larger person would be.