As stated carbs open, plugs out(easier on starter), battery on charger to ensures it does not get weak. Engine warm is essential, particularly in an aluminum block. Pay attention to the first pump number and then total number. Some engine builders like to use the first pump number as a bench mark as it compares to total. As for a total c cranking compression number lots of variable there for sure. Aluminum blocks will generally tend to have less cranking compression that their equally done iron brethren.

As for leak downs a lot of variables there. Good to fund think like slightly bent valves etc. I think if you ask engine builders they would rather see a cranking compression number over a leak down number as to engine health. If you ran a vacuum pump that is another way to gauge the engines overall "health". If that number begins to fall you will likely see that in a compression test as well.