I’ve heard, anecdotally, that smaller centipedes deliver a worse “bite” on account of the venom being more concentrated. Or maybe that was scorpion stings? I dunno.
I allow Pholcus phalangioides to live in the corners of my place, because they’re far preferable to the houseflies and mosquitoes that they keep under control. I wish they’d clean up their webs when they relocate, but it’s a small price to pay. Aside from being untidy they’re not bothersome.