I cannot find a definitive layering of aubergine/eggplant, meat sauce, potato, bechamel and cheese for 'authentic' moussaka: quite a variety in the order from good sources. So, what is the best order for my priority; portions that plate well ie more brick than puddle? Either fresh and hot or plated and reheated from cold? 
As with lasagna and other casseroles, the secret to making moussaka as "dry" as possible is to make sure that the ingredients going into the casserole dish are as dry as possible. The order in which you layer the ingredients makes no difference. This would include:  Making the bechamel extra-thick (high flour-to-milk ratio) Make the meat sauce on the thick/dry side, by searing the meat dry and cooking it down quite a bit, and maybe increasing the proportion of tomato paste Precook the vegetables as dry as possible.  For the last tip, you have some different process options to make sure that most of the water is out of the veggies before they go into the casserole:  Oven-roast or air-fry them instead of shallow-frying Fry them until crispy, then carefully blot off all excess oil Fry them as normal, but dry them in the oven afterwards  I've personally used roasting method, simply because I've already got the oven heated for the eventual casserole.  It works for making a more cohesive moussaka, but does change the taste and texture compared to the version I've had at Greek festivals, where having a ton of oil is considered desireable. 