If the aircraft is to be used mainly for aerobatics, why not make a straight swap? The co-ordinator might be handy if doing instrument flying, but most aerobatic aircraft don't do much of that. Have you got an aerobatic AI, with a good caging mechanism? We had to fit an expensive new one in our Cap 10 last year after someone renting the aircraft bust the old one, aerobatting without the gyro caged. There's a naughty video shot of the new AI rolling 360 degrees on the aircraft's website, but that's for marketing and we've told him not to do it again!
Lastly, if spinning inverted and confused, the rudder which offers most resistance is the one to stomp on for recovery.