I use it on the side covers and cam cover, too. Just one side (the cover side).
Sealant on all your red lines is good: You won't need it down that middle rib now, though.
When Honda mated the cases they used an (old-style) silkscreen mask that laid on the case (lower) and then they squeegied on the sealant in one wipe. Very fast and effective, and very even, using a minimal amount. After the crank's bearings are all seated, reassembling the cases without the sealant at the main bearing bosses provides a (very) small reduction in case diameter, which is perfect for re-setting the bearing shells tightly. To find out how much this (very) small amount might be, I once tried a set of otherwise useless (chain into the backside) cases with the crank complete. I was surprised to find it was enough to show up in the Plastigage as 0.0002" smaller without the goo. That's sort of like shimming the used bearings, which was a popular pasttime on the farm with the old Ford tractors and their striaght-6 Ford engines: those got thin sheets of shim steel behind each bearing shell (5 mains in the 170 CID Ford Tractor Six), and in the process I learned it was very common to do this with older cars during WWII because of bearing shortages during those days.
In many of the 550s I have taken apart I find they benefit from not using the sealant around the main bearings, too: it seems like they often have marginally loose bearings...like more than 0.0022".
