Balls!

[darrens]

Spoke to Midland, they don't have one

[jamiem]

Just buy these and do what i did: Evolution RC,Rockamp,Kokam,Align,Beam,Rave,Wera,Synergy,ElyQ ,Scorpion,Rapicon,Spartan> Home > Rc Helicopter Spares > Synergy N9 - N5 - SE > Synergy N9 Spares > SYN-107-108 - Chromed 3mm- 3x7mm Pivot Ball, 5 per bag (5)

[chugga-bug]

The hypersizer is the "correct" tool for the job, but the one i tried a while back was blunt as anything, and did nothing what so ever.

I'll second that. I borrowed one to do my N9 balls and it was utterly useless.
Making your own is the way to go.

[Smoothound]

I have an adjustable ball sizer of some description but it was no good for the N5 balls. I just did as above, there are a couple of spare balls in your spares bag