I'm looking to buy an Experimental for low-cost time building. One of the commonalities of many under $15K planes is Rotax 2 stroke engines. I am trying to determine if a 4 stroke is worth the extra cost because I am planning to purchase this plane as a first plane, not as a long-term plane.

My plans for the plane are:
Own 2 years or less and Fly 200-350 hours.

This will mean that I will pass TBO on a 2 stroke Rotax, so I will need to budget for at least 1 overhaul. I have a mechanical background, so I am confident that I can do the overhaul myself, but I want to budget based on me removing the engine and sending it off for an overhaul. I am concerned about know that I will experience an overhaul, but I also find the low cost of overhaul or replacement appealing because it means that unexpected expenses like an engine failure or prop strike will cost less than on an O-200.

Because it has a huge impact on every decision we make about airplanes my planned mission is:
Fly enough qualify for a commercial ticket - Primary Goal
25% - Local, in/out of same airport flights during the day (Just fly)
25% - Daytime VFR XC Flights
15% - Night VFR XC Flights
15% - IFR XC Flights, including IFR training - Planning to rent a plane for these, unless there are low-cost options to fly in my experimental
10% - Just Fly Night Flights
10% - Carrying Friends on Overnights and Vacations - Planning to Rent for these, due to needing to carry more than 1 passenger

My questions are: Is there anything I am overlooking with this plan? Is the Rotax 2 stroke the best option for this plan, or is there a cheaper way to fly (even if it means more up front)? What should I budget for an overhaul, or should I just budget for a replacement engine after TBO? What questions am I forgetting to even ask (aka, what don't I know that I don't know)?