Patching and Plastering - Gypsum to cinder block transition

Gypsum to cinder block

Hey guys,
I just re rocked a utility room. Id like it to appear finished but perfection isnt that essential since its just a utility room. When i put the new rock up i brought it within about 1/8th to 1/4" of a cinder block chimney that goes floor to ceiling. the chimney vents the hot water heater ONLY. the cinder block is painted.

My question is, how do I make the transition from the sheetrock to the cinder bock, they meet, and form a 90 degree inside corner. there is a stud on the corner where the cinder block and sheet rock meet.

where the chimney goes through the ceiling also has to be transitioned.

my thoughts so far were...
1) spackle does not adhere to painted cinder block so simply taping an inside corner would be out of the question (i think)
2) too big a gap for caulk.
3) use a piece of quarter round, then finish nail it in the corner, then caulk that piece....
4) i could use crown molding but the edge of the block is pretty rough. and you really cant fasten anything to the block itself....

so im not sure what to do here... my head tells me the only option may be the large peice of quarter round, and caulk?

thanks guys
Kevin

You could trim it like you said. Or you could flat tape to the block. That means you fill the gap with mud then put a piece of tape that butts up against the block. Then you can caulk that. Or you could use whats called tear away bead or rip bead. its L bead with a guide piece which gets torn off when you are done.