In reply to mutt:
Really? I've never seen or heard of that.
I don't think you can really answer your OP as it it depends almost entirely on the type of route and the climber. For example if you're a beast doing 1-5-9 on small rungs is probably British 7a and could be done in wellies but a 5b climber doing a delicate 5b footmatch would be struggle without rock boots.
IIRC the Fitz traverse was done in approach shoes and that was F7a but an onsight first ascent, moving together and carrying gear if that helps you.