Hi

I did not follow recommended place to install battery packs as I found that if using the recommended CG (175mm) that the plane was to nose heavy (for my flying style any way). Most of the pilots I spoke too had the same problem. Currently my battery packs (TP 5300) are placed on the landing gear plate so I only require little down elevator when inverted and plane now balances out on the recommended CG. Still found the need for little up elevator and plane was tucking to canopy on down line. Increased stab incidence that took away up trim (about two cliks) and also no more tucking to belly. You could also play with prop sizes, APC 22x12 weight 116g, 21x13 weight 130g (recommended for Hacker) and 20X12 only 86g. I am using the 22x12.

Regards
Burt