Thus far with no issues:
I use 1S 80mah with my 1.7g / 2.2g servos - TD .010 / 130.4 mph
(engine moved to new plane for next level testing)

4cell 140mah with 2.7g / 3.7g servos TD .020 / 106 mph
(engine moved to new plane for next level testing)

4cell 270 mah with 4 to 7g servos TD .049 / 122 mph
(still prop testing room yet, will need a new plane soon)

4cell 400 mah with 9g servos TD .09 / 148 mph (done needs a new plane)

Next summer I will do more testing with the TD .01 / .020 and .049 I am done
with the .09 as it will require a new plane to go faster. .049 will need a new plane
after a few more tests. 4x5N will be it's best prop leaving enough thrust on the plate.

I like high torque over speed for servos and of course small cases
for planes up to .049 is a must. I don't like thirsty high end servos.
Will be putting a TD .15 on something new for next summer. Such broad
prop selection 170 mph is possible. 5.5 x 6.5 should yield a frightening blur
28k down wind. 14g -17g servos / 4cell 600mah range.

4 to 5 flights per session is enough for me.