Amplification for big band

Hello! I’m about to rehearse with a new big band in a couple days, and have some concerns regarding amplification. Ideally I would like to bring my upright, but I don’t have a functioning piezo right now. But I do have a sm57 and mixer+PA speaker, and was thinking I could do the towel/foam thing. Whats the best way to mount/position a sm57 for minimal bleed? Is that even worth the hassle or am I just gonna drown in feedback/bleed in a bigband-setting? Worth mentioning could be that we’re mostly gonna play softer Basie-tunes, and the band/drummer is great at playing sensible! The rehearsal space is kind of small though. What do you guys think, is this possible or should I just bring my electrical instead? Cheers from Sweden 🙏