Beg, borrow, steal or buy yourself a Yak 52 and get to North Weald in Spring for the formation flying school taught by RAF QFI's and highly experienced civilian pilots with hundreds / thousands of hours of formation flying. Compton Abbas also hosts plenty of formation flying weekend, also in Yaks.
You will see that the SOP's for formation flying run to 15-20 pages of closely typed writing. These are there for a reason...
As someone who was a complete novice at the art 2 1/2 years ago, now flying with a formation display team, I can only echo DB6 and others - get a lot of professional instruction - both of you. Safety first - enormous satisfaction and fun will follow shortly thereafter.
Enjoy.