Siroma usually lasts you a lot, on the simple stance that while it eats really often, its food only weighs 1 unlike most other pets out there. You feed it more often but the trade off is that even its food is very weight-efficient.
Would advise against the card combos, as those card combos for the most part are very outdated for one reason or another to the point that it infuriates the users more than help (read: Kadar and his card combo for WoE that used to be a secret brilliance but no longer work due to mechanic change).
TL;DR: Like Marivel said, just play like a priest, only that you heal more, can assumptio, and got more stats.
It made me able to tank mondo amounts of monsters where I couldn't before, as well as stronger ones themselves and in small groupings.
Anyhow, transpriestgasm aside...I looked at the acolyte combo, and it only looks particularly good over some things. I think I'd be better sticking with my goibnes, till I can overup a ton of things and slot them with rares.