I think you had a few typos that make it a little confusing.

I chose the LEOM (Leo Miner) instead of LEOMM (Leo Mega Miner) for mining of LEO because LEOMM mines 4X as fast as LEOM. LEOMM is at a cheaper price of 6 Steem/LEOMM whereas LEOM is 2 Steem/LEOM.

I believe you mean to say you chose the Mega Miner.

There are 30 winning miner tickets per hour meaning that only 30 LEOMM holders win each hour.

This is not accurate. A Mega Miner (LEOMM) can win up to 4 of those 30 tickets. A regular miner can only win once. So a single LEOMM has the potential to win 4 of the 30 slots each hourly lottery.

So investing 300 STEEM to buy 50 LEOMM, I get a return of 2 STEEM / Day!

Keep in mind, this will drop drastically over time as more people buy LEOM and LEOMM and stake them. in fact, it will likely cut in half in a very short period of time (days? potentially even hours).

The price for LEO will change drastically over time and may go up or down affecting the daily estimate considerably.

Good post just wanted to point those out.