My opinion is to go with the MT-12 and then get a starter box.

I never want to see another one of those pull start engines again in my life. I had one on my first O.S .12 engine and it gave me nothing but trouble. It worked good for a couple of weeks then started having problems.
I have had my starter box for more than a year now and it has given me 0 problems. I would suggest the Ofna box with a 12 volt cell. I have the hobbico 12v 7amp cell which seems to last forever before needing a charge.
I can run my glow heater and charge batteries off this cell when I need to.

Once you have had a pull start and go to a box I think you will be glad you did.

Dbow