what is the nowadays typical roi of 45man and 180man sng

A typical ROI is hard to determine. In the end it pretty much depends on your skill level and the limits you are playing. 30 to 50% ROI should be quite good I assume.

Not sure about the 45men, but I think the ROI should be a bit lower there.

Which one is more profitable is hard to say as well. Again, it depends on your skills. An equally skilled player should be able to play 180s more profitable, because they allow for a better hourly.

However, that's just a guess from my side.

Regards,
Asaban

As Asaban said it hard to determine, as you can play 6 tabling 180s with 40% roi, but your hourly will be way lower than 20 tabling with 10-15% roi.
Over large samples best guys have 20-25% roi from what i have seen, standard/solid regs have 10-15%, so if you can achieve 15+% over 5-10k games you know you are doing good. 180s are getting harder and harder to beat especially 8$, 15$ and higher.

I play only 180s so dont know exact numbers about 45m. Just check out sharkscope leader board.

how long does a 180 man take? are <$2 beatable for newbies looking to grind up a roll?

Till the HU ~90-100min, but it depends how fast players bust, at least 2.5s, in higher stakes it prob takes a bit longer and in 3r 120-150min something like that.

It will take some time and discipline but it should be doable to beat <2$ games, once you have understanding about nash push/fold, you should be able to crush those games, but i haven't played anything under 2.5$, so i cant be sure what is the the player level in these games.

I don't think I ever played one that lasted longer then two hours. Not sure though since I never look at it while multitabling.

Regards,
Asaban