If the pushrod tubes are the same as on the big bore Continentals then
the cylinders do not need to be pulled, you just need the tool to
compress the springs. And no mechanic worth the title uses loctite on
those tubes. If you get the gaskets in right they do not leak. Very
easy to tell with a little mirror.

The O-200/O-300 engines have the pushrod tube swaged into the cyl head
assembly. There is an elastomeric seal at the crankcase end only. I
understand there is a re-swaging tool that I assume you already have
used to tighten these joints, but that tool can only do so much before
it damages the tubes etc. The use of loctite is appropriate.

I thought someone had mentioned it earlier (maybe on another post?) &
I've never tried it, but perhaps you could pressurize the crankcase
thru the breather line to maybe 1-2 psi & do soap bubble tests. Don't
go any higher or you would probably blow out the front crankshaft seal.
BTW I assume the front seal has its split in the correct quadrant?

Chances are otherwise pretty good the leak is around one of the case or
pan splits, in which case a vaccum should be used to suck in a sealant
after cleaning.