Th OSSA phantom ignition will fit under the newer style side cover as will a PVL ignition. The desert phanton ignition cannot be used on a MX phantom unless you swap the crankshaft halves, the desert phantom ignition will not fit under the newer style sidecover.
I know that it is a bit pricey but a PVL or MZB ignition is probably the way to go. the swapping crank halves is costly and I wouldn't have done it had the MZB ignition with the lighting been available.
When my desert phantom engine motoplat dies I'll be replacing it with an MZB, My GP3 engine uses
a PVL and my GP2 engine has a rebuilt Bradford motoplat.