Any tips gratefully received.
If you're swimming in credits and don't plan on using your available module storage space for much of anything else, I'd say go for it, but I honestly can't think of ever wanting to use prismos on that many ships. I'd rather module swap on the rare occasions that I wanted to change the role of a ship I already had.
To me, prismos are "great to have, time to run when they go because they're never ever going to recharge", so I'd only ever put them on traders, miners and maybe explorers. Ships that I don't intend to ever fight in with a few exceptions. Rocking up to a CZ in a 'vette or cutter with prismos and then just camping with turrets while scooping up mats, perhaps. Or, of course, a 1v1 PvP with that nemesis that I just have to defeat just once.
But for extended combat ops, I personally wouldn't ever want them. Better to have better speed and boost to be able to run away for a minute or two while the shields recharge, then be back in the fight.
So I'd look through the ships that I would ever likely want to fly, then buy one to fit each class and be done with it. But that's just my opinion.