I too found the RTV sealant for the o-rings to be a surprise when reading the book. Seemed odd to have the o-rings pasted in place with the sealant. The o-ring itself is the seal and applying sealant to it took me as redundant? Dunno. I'm no expert by any means. If it works for someone else, great!

Had I not even read of the RTV method, my method of addressing the case o-rings would have been the use of an o-ring lubricant. The type I use on o-rings is the famous Dow Corning 112 Valve and O-Ring lubricant. It's like a silicone paste that doesn't harden. Always stays pasty like grease. Since the 112 is solvent resistant is protects the o-rings from oil contamination. Just don't want to use too much. Blobs could get where you don't want them to!

Dow Corning 111/112 MSDS pdf link