Ok, many questions here, and some car stuff as well, which in the context of running in seems allowable.
Pat - I have this oil in stock, and also took pictures of the cylinder, see below. The exhaust port is clean. The little black in the head was so soft, it could be washed out with gasoline and a pig-hair brush.
The engine test results are published here: http://www.prme.nl/forum/viewtopic.php?t=166 I used canisters, tuned pipe and a two chamber pitts muffler, checking plugs in between and adjusting the H- needle as required. This test was done after the engine had been run in on the MVVS 3204 canister muffler using a 24x10 Menz-S prop. This large prop was hard on cooling, but no special provisions to improve the cooling had been taken. Test CHT ranged from 140C to 200C, depending on mixture settings.
For the oil, see http://www.putoline.com/en/product_d...2&catalogId=94 for info. The new MHX oil looks very promising as well, because it allows a wider mixing ratio of 1 - 4%.
The RS959 that I use is primary an injector oil that can be premixed. In my oil tests at 200°C, it flashed off quite short (probably the lighter premix additives), and thereafter did not oxidise quickly, but spread out without drying out. After 20 minutes at 200C it still was quite clear and thin, and could be wiped off the test plate very easily. (Under these conditions, Castor had dried out and polimerized completely)

I have been busy repairing the jug, so it can take a spark plug again. Brass tapered insert, just like they used to repair old worn out spung (?) holes in bronze canons. (the hole used for igniting the charge.) Foto included. Lesson learnt: do not check plug readings in a hot engine, but let it cool down first. The short reach plugs have so little thread length that it should be treated with a bit more respect than I did.