I took the muffler off and drove around a bit yesterday...with ear plugs...it was loud! I didn't detect any difference in the way it ran. The exhaust seemed to flow fully when I put it back on.
I took the spark plugs out and cleaned and set the gap again, too. All bolts to the intake and exhaust manifolds were tight. I saw your idea regarding the sediment bowl today. I looked and it had a 1/2 of crud at the bottom. I cleaned the crud out as well as the screen. That just may have been the issue. I will definitely monitor that better in the future. It was too muddy and sloppy to take out for a test drive.
I am still unsure on how much blow by is acceptable. There is a steady stream of air blowing out....just more noticeable when it is cold?? It doesn't seem to be losing a lot of oil when I check the dipstick.