you mentioned buying from ebay, does that mean you didn't go to a shop and try them on first?
that would be the first thing if possible. you can determine alot from there. I currently have an Icon Airmada helmet in 2xl (or 63-64).
it's good but not great. fits well but there are too many vent openings so gets more wind noise than i'm used to. i just keep most of the vents closed -even in summer, and that helps.
best helmet I ever owned was Shoei RF1000.
but when I got back into bikes last year I went with something I could afford to start with. maybe this year spend more money and upgrade..
even if you're able to try them on , that won't tell you what kind of noise it will make when riding.
also some helmets will have replaceable cheek pads in different sizes if that's the only problem with the fit.
lastly -Revzilla (and i'm sure other websites) have pretty good video reviews of various helmets, detailing size, fitment and sound, shown on an actual person to give you a better idea.