@tomic601 ,
I actually use his Super Stiff Springs on the lower shelf.
I got some slightly higher load rated springs from Grainger for the upper shelf.
(It’s a work in progress.) as the VPI is way heavier that the Rock 7. The BDR Shelf for the Source weighs around 70 lbs?
BTW, I use Geoff’s lighter weight/cryo springs under my Hydra 6/Symposium set-up directly under the new set-up....along with 4 Stillpoints Minis.
What overall weight are you looking at?