@op. perhaps i am a bit late posting in here,
but i'd like to give my thought.
All previous said is right but you missed considering a very important point (maybe the most): the bankroll management!
Because mtts are high variance (not close) u are supposed to play them with a larger bankroll than other games type. Now i read so many different thought about which is the correct BR to grind mtt vs sng so I'll say my personal one: which is that u should be rolled 300x for mtt vs something like >80x <100x for the Sng (according with the tabling and the structure type: es turbos or not).
So my advice is: if u do not want to go broke just keep on grinding sng and as soon as the BR increase u may add some 18/45 ppl then 180 max.
Whilst playing them add rdm freerolls
(like CC freerolls which I never played but I suppose got good field coz of the selection the site do - 65 quality post + 30 days activity = less random ppl)
U might even add some mtts (1 or2) while u playing ur session so, supposing u got, after 2h of play, a deep run, u can continue and enjoy(/practise as well) the mid stage.
sry op if i didnt clarity your mathematical clue but Imho the point just above it's the most important thing to consider for a right choice on what to play. your favorite game apart.
gl and let us know your choice!