Since you say you have battery ignition on both, I would think it would not be Moisture inside the Caps..
On a Mag, I have had that problem countless times..
NEW Sparkplugs would be one of my 1st moves (Autolite#3116)..
Mud-Dauber nests plugging the upper air inlet stack can cause them to SMOKE BAD under a load..!!
I use a cut off garden hose up through the air cleaner (Water ON)..(oil cup off)..to clean them out..shove it all the way to the TOP..
Moisture on the plug wires or plugs can be a problem, too.
I would not worry about getting a good Compression test, until you get it running, so the cylinder walls are properly lubricated.
Have you CLEANED the ignition Points..??
Not likely both have had Condensers fail...
I have a Condenser tester that I use that is mighty nice to have...