Get yourself a TMG Class Rating - then you can use hours flown in either a SEP Class aeroplane or a TMG towards the revalidation of both Class Ratings:
If the licence contains both SEP (Land) and TMG
ratings, the revalidation by proficiency check
requirements above may be completed in either
class or in the case of revalidation by experience in
either class or a mixture of the classes, and achieve
revalidation of both ratings.
(from LASORS 2008 F1.4 - complete with lousy original grammar!)