I just placed an order for a Ries A250-2 head to compare with my Arca Swiss Monoball B2 head. Both will be used with a Gitzo GT4330LS tripod. This set up is for a Deardorff V11 which weighs in at 28lbs before lens. The only potential "issue" that I anticipate running into with the Ries on the Gitzo is the absence of panning which is built into Ries's tripods and consequently not built into the heads. I've read a few discussions regarding this and overall people have found various solutions and many state that it isn't bothersome for the most part. In an effort to cover my bases I've been looking for large panning bases that could be put between the Gitzo and the Ries which would provide panning if I decide I need it and want to keep the tripod head combination.
I've read a bit about the FEISOL PB90 panning base which is low profile and rated with a load capacity up to 83.8lbs which is more then enough for the V11. I'm wondering if anyone can offer accounts of using this panning base to provide panning when using a larger Ries head with a Gitzo. I'm wondering if the difference in diameter of the FEISOL surface (3.5 inch) and the Ries (6 inch) would be problematic or a weak point. Any help and insight would be appreciated. Thanks!