I would just take them to a welder and have him remove the 944 "collar" and weld it onto the MaXX strut.

However, with the use of Topline's camber plus kit and the H&R CCC bolt (see note below) you should be able to get enough negative camber.

Note: Volkswagen itself makes a bolt simular to the H&R, part number N903334.01 this bolt was used for crashed cars that needed extra adjustment in their damaged carriage. This bolt will give +/- 1/2 degree of adjustment (+/- 1 degree if used on top and bottom of one strut).