files ABSOLUTELY nessecary for a custom rom to boot

[imaginethis1]

I have recently been building custom roms with Calkulin's Kitchen for the Touch Pro2 (i'm a rookie so be kind), and I have been wondering which files/packages are absolutely nessecary for the rom to boot and run. the reason I ask this is because i cannot find a way to keep my RAM use low. it's usually in the upper 50% to 60% even off a boot.

thanks for all the help, much appreciated.

[Rager02]

I havent done much cooking ive only tried sprint basics kitchen and one i did was pretty low on ram,but i was told key to becoming a good chef is trial and error.in that kitchen its pretty clear what are apps and what isnt.try out different things until someone can answer this better than i can.

[gmfeny]

You could try Calkulin's Rom posted here meant for running Android.
He has 2 versions available a 6.1 and 6.5.