I would suggest using 48P if you are in a carpark. Little bits of girt and stones on an un-prepared surface chew uot spursa like nobodies business.
w.r.t. FDR, the standard TA-05 has an internal ratio of 2.25. For the MM, the 70 spur will be way too small, you won't get a pinion small enough to get a gear ratio that works for racing.
For the 27 turn, i'd start with an FDR of 6.5 and work from there. That's what I raced on before brushless in my TA-05, but it depends on your track size.
For the MM, the FDR is going to be more like 8.5 to 9.5 to be in any way useable in a race.