Hop absorption rates?

Just finished (phew! Only 10 hours!) brewing the massive 1.115 imperial stout tonight. I had accounted for grain absorption, but as I finished filling my first 20L fermenter and heard the march pump straining, I knew I had forgotten to take into account the absorption rate of nearly 1.5 pounds of hops. How does one calculate that exactly?

Furthermore, WHY does it always rain rain rain every brew day?

I go on the assumption that 1 oz. of whole hops absorbs 12 oz. of wort.  That seems to be pretty accurate for me.

Is that whole or pellet? Or does it matter?

IIRC, hop pellets are chopped up hop bits, whereas leaf hops are desiccated, therefore the leaf would do the absorbing and not the pellet.

Both whole hops and pellets have been dried to the 8-10% moisture content, so they will afbsorb the same.  Whole hops have more nooks and crannies to trap wort.

If you use a SS china cap strainer (extra fine mesh, i.e., bouillon strainer), you can pretty much get all the wort out of the hops (pellet or leaf) on the output end when transferring into the bucket.  A few shakes pretty much makes a big ball of hop “dough” that is easily discarded.

Whole