Falafel Sandwich Height (Falafility Theory)

Is there any relation between the size of the cola can and the length of the falafel sandwich.
I mean is it an algorithmic relation or an exponential one ?
Does the height of the Ka3keh - when standing without the cover paper - gives us a hint of the right bottle size ?
I heard that the number of "7abaat el-falafel" is a major part of the formula ?? Using the "falafelic scale", which has nothing to do with the metric scale, you can determine the exact size!

2 and less falafleh per ka3keh (falafleh/ka3keh) -> No need to purchase cola.
3 falaflat/ka3keh -> a 150 ml is enough
4 falaflat/ka3keh -> a 300 ml is just fine
5,6,7 falaflat/ka3keh -> a 500 ml is a must
>7 falaflat/ka3keh -> 1 liter bottle or family-size

I saw two guys eating a "falafel ka3keh" which has 4 falaflat and drinking a 1 liter "PEPSI" bottle.
They were holding the 1 liter bottle as if holding the normal-one-person-size-300 ml-can.
It just didn't seem to fit.
I wonder if they are using some other scale.
Maybe they measure it by studying the ratio between the falafel and the salata (salad).
Or maybe the type of bread involved. Ka3keh, 3adi, tandoori, 7amam, etc..

A more accurate scale has to take into consideration correct measures of the radius of 7abet el falafel, with or without hot sauce, etc...

Does the number of "7abat el-simsim" on the ka3keh count ??? :D