stopping gasket leaks

Yes and yes.

Yes baby powder or chalk dust is fine- yes you need to clean it before applying powder- keep the speed down or you will blow the powder off

After a couple hundred miles last weekend, we observed oil at the bottom of the engine. The half moons were dry and we observed nothing else from above. I believe it may be the shaft seals for the alternator and the ignition. The gaskets for the two covers for these are only dust and exterior protection, not oil gaskets. I'll remove the covers and clean up the oil mess and replace the seals. In the Clymer manual I do not find instructions on how to only remove the seals. Of course the alternator must be remove and the ignition. I'll search KZF for a procedure on how to do this, but does anyone have tips or instructions, again removing the seals for the shaft at each end. Thx.

The easiest way to remove seals in situ is drive self tapper or dry wall screws into the face of the seal on opposites sides and work them seal out with  two pairs of pliers

Before you go thru the hassle or continue thinking it's the LH and/or RH crankshaft seals. Neither of those seals, if leaking, would explain why original posted photo of having oil on the cylinder/head fins. Oil won't defy the laws of gravity and be sitting where originally shown. Unless someone spilled some from a can somehow? 

Yes there still could be something from above, but a careful check of half moons, head and other gasket areas in the upper did not confirm leaks. But I will continue with this. We'll see what's in the left and right chambers behind the covers. I am preparing to replace shaft seals by finding the procedure and instructions, then ordering what I need and probably cleaning and installing the new. Thx.