Crest and dips are a problem that befalls the commercial guys too. E.g. original runway at Manchester has a big rise about 1/2 way along.
Hmmm...for a Europa to have a problem, the frequency of peaks must be high given the a/c's short landing distance?
My theory - armchair advice this Mr D... Your problem started with the protracted float, so keep the speed down to minimise it. Land on a uphill part with this short-field landing config. Make sure you don't have too much float/lift under wings as this will mean the subsequent crest acts as a ski-jump.