The joggle worked out great and I marked out the rivet positions using standard aircraft practice for spacings for the 1/8" and 3/32" rivet locations (Aircraft Sheet Metal page 28 Fig 4-2).
I then drilled the holes, clamped the doubler in place, match drilled and clecod.
Had to back drill the joggle from the underside of the skins.
I then drilled the required holes for the antenna and the initial fit worked out great.
I did exactly the same on the other side for the XPDF antenna doubler
I am glad I did this at this stage as the access is easy.
