You start and make adjustments almost the same way as if the engine were not inverted. One difference should be that you turn the prop through a few rotations before applying the starter to make sure that there is not so much fuel in the engine that a "hydraulic lock" might occur which could result in a bent connecting rod. As for adjustments, the needle valve should still be easily accessable only on the other side of the fuselage. With some in-cowl engines you might need to put an extension on the needle valve so that you can adjust the mixture.