[KTL]

That thin gasket is fine. The mating surfaces of the chain housing and engine case are a bit messy so it's good to clean those up with the vertical razor blade trick and then coat your new gasket with the sealant (thinly applied!) of your choice.

As an example of how this area is fairly sensitive to alignment, my racecar engine has apparently been built and rebuilt a number of times. So the heads have been cut a few times (they're now below min thickness & next time i'll have to find some good used heads to start over), somebody decided to surface the former cam housings once, and it's common practice to surface the chain housings the same amount the heads have been surfaced.

All that being said, when I assemble my left bank (1-2-3) I cannot use a thick gasket on the chain housing because the alignment is WAY off. Plus the chain tensioner is quite extended (will be using a custom larger sprocket on the tensioner arm). I just use some Curil T to seal it up. Works just fine since its splash oiling. Even if it was pressurized oiling, you could still use Curil T because it's a good non-hardening flange sealant.