I too have done it with old, primative type engines (compared to the Volvo white engines) BUT having had white engine cyl heads off before, I highly doubt that you could do that with the head on.
Before wasting time (my opinion as I doubt that your valve guide seals are the problem), has anyone checked the engine with a cylinder leak-down tester? That's THE BEST way to check an engine for compression loss BEFORE taking it apart.
I suggest having that done first because I'd suspect bad piston rings or if turbo, turbo seals over valve guide seals. I have yet to see a white engine with bad valve guide seals and even if so, that will usually only cause smoke when first starting the engine and not be a cause of major oil consumption. If it blows clouds during hard excel., that'd be rings or a turbo prob (IF turbo).
If not turbo, is the flame trap/PCV system OK?

It seems like you have the know how and tools to do the job.
I have done a few on import and domestics but never on a Volvo either.