Hi team, need your help. I have fitted new WP progressive springs, but am wondering if I did it right

The instruction seems applicable to completely disassembled fork legs, whilst I did mine on the bike.

I lifted the front up and took the old springs out with the spacer bush and fitted the new springs. I then filled up the fork until the free space was in accordance with the instructions (170 mm), but upon completion of re-assembly the fork feels like concrete pillars. I'm now wondering if I should have filled and measured the free space whilst the bike was standing on the front legs (ie not lifted and the fork in as low a position as possible).

Anyway; anybody done this before and how did you measure??

You may have answer your own question.
I always fill my fork measuring the quantity of oil and didn't know about this 170mm.