95 ranger wheel cylinders/drums

[95rangerxlt3.0]

Hello everyone, quick question: I replaced my rear wheel cylinders with 10 inch ones, I had measured my drums and it comes to a tad under 10 inches (widest part), I've read on here that I'm supposed to have 9 inch cylinders/ drums on my 2wd. I bought the truck used so idk much about what was changed, so i was just going off what was already on it. I have already replaced the cylinders on both sides, (not new drums or shoes though), my peddle feels kinda mushy but not that bad. So i was wondering if i installed the wrong ones or if anyone has some advice.

P.s. any thoughts on seafoaming the crap out of it, it has 194k miles on it, and it has never seen much maintenance...so i also want to know if this should help clean it on the inside.