I've got seven of these now, and I'm wondering if I'm only limited by AP and self-inflicted wounds from doing a multi-turn chain freeze.

Is it OK to equip this many, if you can, or should I plan on selling a few?

You can equip as many as you want, no limit

The limit being, as you said, your APs. Shrieks are one of the best scrolls to mass equip, however they are not adapted to every situation.

thank you for your answers. I got a lot of boosting to do!

If you are going to use them, then it may behoove you to keep them... the fail rate on freezing scrolls is terrible. Not that they are really needed... Blue Ball can be beat in BQs without them ( well depending on your stats and whatnot, of course ).

Oho, that's good to know. Mostly I was amused by the idea of doing a massive chain freeze, just for the crazy fun of executing one. Since I was an idea just for fun, I didn't want to massively boost and tome my main pet without checking first to see if it was even possible.. Glaciating Pylonic, Mercurial Throwing Vial and Ultimate Tag all have medium freeze rates, so maybe I should plan on only three Shrieks in conjunction with these, and sell the other four.

It's true that I've been having difficulty with Sophie Slaughersaur and Prodigy with my T12 3600 even statted pet Magentawhimsy, but it's also true I haven't tried very hard or researched how to either. It's quite likely I do own the necessary weaponry and scrolls, just need to fiddle around or ask and I haven't done that yet.