Hi Harry
From your recent post I assume you are doing this on your C15 without the body installed, which makes it easier than it will be once the body and nose are there, and we won't even talk about trying to do it on Pat 11 and 12 on those even once you remove all the dog house sheet metal it isn't easy.
There have been several good threads on this in the past that had some useful information take a look at
http://www.mapleleafup.net/forums/sh...ad.php?t=11791 About half way down the page there is a post from Keith Orpin with a useful bit of information about which cylinders can be done at the same time if you are using the engine not running approach.
Concerning oil splashing around with the cover off is minimal even with the later 261 with 40PSI oil pressure. Take a look at some of the engine video on my web site you can see the engines running with the covers off.
http://canadianmilitarypattern.com/EngineTesting.htm take a look at the 235 videos they also show the engine running with a clear side cover on the test stand.
For me I seem to get better results setting the valves with the engine hot not running. Have done it both ways with the engine at room temperature with the engine on the test stand just to get a starting point. Then later when the engine has had a chance to run in with the engine hot. Biggest issue is to wait until the oil in the engine has reached operating temperature so the whole engine is really at that 160-180 F range. When I'm doing this on the test stand I use a water jacket block heater. Which will maintain the block temp for a long time after you run the engine. Minimum engine run time to get to equalized temperature assuming 68-70F air temp is about 1/2 hour.
Cheers Phil