well its the little things that can stump us everytime....well judging by your compression test and verifying 160 in all 8......thats an indication that rings are doing there job and sealing it up......Another area that may be looked at is are you running a pcv valve in the rocker covers.....it could be that the crankcase is building too much pressure and forcing oil past the rings and guides..........If you do have one maybe its not doing its job......another indication of this is that all the plugs are oil fouled.
thats why i suspect the motor is building too much crank case pressure......give that a shot and let us know what you find ans the solution...........that lithium grease will discipate with heat and engine oil........its also known as engine assembly lube.....I use it and have not experienced a problem with it....just make sure you change the filter after camshaft breakin cause it will plug the oil filter really quick.