When I play MM, I pick combinations from all 56 numbers. I may not used them all but I consider them all equal. The only numbers I pick are the mega numbers which I have to do since I only play 10-15 lines, not 46.
I've never found a way define regular numbers as hot. I do consider some mega numbers more active than other and usually used the top ones as my mega numbers but I might do as well by just picking a random number between 1 and 46.