24.3mm LIPO in DEX410

[GML]

I've just finished a V3 and I want to test it with SMC lipo battery. They are too tall for the middle hole of the battery holder and I have play with the upper hole wich is for 25mm batteries.

I can't find any pic with these lipos and I want to know what's the best way to maintain it correctly (with some plastic card or other)

Or is this play normal for the flex of the chassis ??