Roamio questions (basic model)

I just ordered the 4 tuner Roamio because of the OTA capability.



Now I am wondering about the 4 tuners. How do they work with Minis?



Can we only have up to 3 minis attached to it and if all 3 minis and the Roamio are on, does that mean we cannot record another channel during that time?



I actually wanted 4 minis but I am thinking that won't work if we all watch at the same time?????



I was thinking of selling my Series 3 HDs with lifetime, but if I need another tuner, I will at least keep one.



Thanks,



Dawn