Diggie

I have a built K20A2 bottom end and I now want to upgrade the head. My power goals are 400whp with a Kraftwerks supercharger. The bottom end is ready to support that kind of power and I want the head to also support that power without any struggles. I was searching JHPUSA and found a Supertech valvetrain kit for K-series, dual valve springs, Ti retaneirs, bronze valve guides, stem seals and either flat or dished valves. When ordering that package I have to choose the Spring seat pressure going from 80lbs, 95lbs, 97lbs or 100lbs. Now that is confusing me a bit I have researched a little bit about spring seat pressure and didn't seem to find anything that could tell me what it really is. So I want to know is about rate of pressure should I choose and why. What would be best?