As for the Krowaz+7 vs the +6, I would really suggest go for the +7. Krowaz+7 is even better than Priest Shell+9. I've alot of clannies who had full +6 Krowaz wanting to upgrade to +7/12 hp since at +7 u get 10 more hp stat than +6, plus another 10 hp bonus from having full set. It's quite expensive but is definitely worth it. At 83 with full +7 krowaz, iron set, and dual rol+3, and adamant+7 you get around 1260 base ac and 1610 with max ac buff.
Coming from experience, +7 krowaz is definitely worth it, if you wanna be a tank priest then it should be a good investment.