574 is tried and true but the cleanup of cured sealant is kind of a drag with today's solvents (weaker). Not a big deal. Just worth mentioning.
I know the chatter you speak of on the main webs. Seems to be the norm on these engines. I've heard some pros say they don't like the 574 goop on the main webs because it can prevent complete bearing "squish" or "crush" as they call it. The 574 does squeeze out quite well, so the residual amount left between the mating surfaces seems quite thin. I would just be sure to spread the 574 or 509 as absolutely thin as possible here.
Regarding the effort required to break the bond, the last engine I did had the orange goop on the webs and it wasn't excessively difficult to get the case apart. But I had used the white threebond 1184 on the case perimeter and that stuff doesn't make the case halves stick together like the 574. So I can't say with certainty how much extra effort is needed with the additional 574 placed on the webs.
Another good solution to the web chatter is sleeving the case through the through-bolt bores. Craig from G2 Performance does this with stainless sleeves and he notches them where there are oil delivery passages for the piston squirters. Also saw Neil Harvey doing this on the basketcase rebuild update recently posted.
http://forums.pelicanparts.com/911-engine-rebuilding-forum/951269-home-built-engine-build-saving-unsaveable-2.html#post9772917