Don't these threads always end with someone posting a thunderclap? Those do affect Pete.
So like, maybe you think Spidey could wear him down - take out his legs or something and then just go to work with some environmental weapon or webbing in the nose and throat. There's probably a case for that. Or that a webbing dump could slow GM enough to prevent much of an attack. But we're just a t-clap away from a temporarily dazed Spidey, at which point the fight is just a matter of time before a bug splat. It's probably not a 10/10 thing in a city environment. But the silent "if you use your powers like you should, not even getting super-exotic" clause in vs. fights means we probably have to side with GM for a majority.
Pym can Shrink/Enlarge things that are touching him without altering his size, that should negate the webbing.
Current Giant-man can also fly fast enough to keep pace with Ironman and engaged in a fist fight with Giant Greithoth (worthy Absorbing man) and survived.
Pym's Damage soak should be above anything Spiderman can dish out..
not to mention the fact keeps all his gear linked to his suit through his "Pym Pockets" and personal A.I. that allows him instant access to it all instantly.
Pym wins 9/10 Mindset convinced me to give Pete 1/10