I decided to change nav cluster a bit, cuz I want all important buttons to be really close. That's what I got after step 1.
Now I thinking...
As I had remapped my Caps Lock to Control, why not use 8 on numpad as Caps Lock (only one of "Lock" keys I really use).
As I don't have any use for Num Lock and Scroll Lock now (obviously) I consider remapping Num Lock to Pause/break, Scroll Lock to Print Screen/SysRq), moving asterisk and minus one unit up, addin one unit + buttong and replacing big + button with Enter. But I don't know if Model M numpad enter can be installed on F...