My saddle packs (in the space of a stick) are flat bottomed and take up the whole height. There is no extra space under my lipo's for any thickness of anything. I could get space if I packed up the posts, but I would still need to find a way of lifting the holes in the battery strap end pins. I might be able to force two spacers under the top bolts of the front bulkhead to lift the pin, but the rear pin has no way of lifting. Maybe if I mealt the arms that come for the gearbox ???
Seems a little drastic.
Anyway, I think I've solved the problem now. I cut a sheet of 0.028" (.72mm) brass to match the chassis. It weighs 138g. Seems people are using the under lipo @ 90g + rear bar @ 30g and under servo @ 25g. So I have a little extra to add using the little wheel weights. This puts the weight as low as it can get and should not upset the balance of the car. If I need a few extra grams, I have a clear chassis on top to place a bit here or there. The brass is very thin, so it can be trapped between the chassis and under tray. It is held in place with just the two rear gearbox C/S bolts. This will still allow the chassis to flex as the front of the plate is only held in place with the undertray. Hope it works !!!