Hola Enis -
xxx
Many factors to consider as to FL level selection. All planes different.
And for same airplane types, how heavy are they...?
Climb/distance to TOC cruise FL depends mostly on their weight/payload.
xxx
With a heavy 747, the best I could hope was some FL280 initially.
And might take some 150 NM to get there.
With the 727 - medium payload, short distance, 120 NM might be ok.
And FL 310/330 was fine.
xxx
The only "somewhat" general rule is point of descent.
With all types of jet airliners I flew... 3 times the FL for distance to start descent.
As example - FL 350 = 105 NM for descent. Correct some for winds aloft.
Using the above data, you could derive an approximate FL selection.
xxx
Happy contrails