I went ahead and respecced last night. In my first cut I was at 26. I saw about a 65 percent success rate in an Elite Deal and the Demon ransack cycle and about a 75 percent success rate in a half dozen Matron and End Farm of Rusted Blades Hard.
I grabbed more gear after the session, so I'll see what a 30 does tonight. With a 26 I was able to to every chest we tried last night. The only time I ran out of blesses was when my ship buffs ran out, so I agree with you that 26 is a reasonable chance, and is right on the edge. Small sample size, but 24 seemed to be too low.