Hi Mark, '69 did not use gasket for inner or outer covers from factory, yet some parts books shows them.
The inner cover locates the clutch in/out position & also controls end play of the gears. If you use gasket on the inner cover you are effectively moving clutch to right which effects primary chain line & giving gears too much side play, plus this can effect the depth of dog engagement of gears. Don't use a gasket on inner cover either.
Outer cover when you use gasket gives more end play to kicker shaft, & shifter shaft. That doesn't help things.
My sealant of choice for both these covers is Loctite 518. Put on dry surfaces it can fill gaps of even .010". Yet it allows you to remove covers later without a fight & can be removed from sealing surfaces without a fight. Trust me, it will no leak when put on dry surfaces. Put on one side only. Not both sides which would give double thickness of 518. That's too much. I use a acid brush from Hardware store & apply light coat with brush marks going long ways on case. Think how a notched adhesive trowel works. Like that. You don't have to assemble quickly, but don't wait hours. Be ready to assemble. Apply sealant & assemble promptly. I let cure 24 hours to be on safe side before adding oil.
Some threads go through to the outside of motor (not blind) it is common for oil to seep along the threads & leak. Put a thin smear of 518 on threads & washer to prevent this seepage. I've been using 518 for 3 years now to perfect results. I don't know how long it will last, but not a trace of seepage so far on a few motors now.