The halving of the maintenance periods is only applicable if you run wholly on Avgas (and many Rotax's do). Basically, all thats required is a more frequent change of oil and filters and (maybe) the spark plugs. In my last 100 hours of operation in my Pioneer, I filled up with Avgas 12 times, with a total of uplift of 360 litres. Total Mogas uplift in the period was 1260 litres. When I changed the sparkplugs there was no visible evidence whatsoever (to me at any rate) of any lead fouling.
As my aircraft's got 4.5hrs and over 500 miles endurance, Avgas uplifting is generally limited to extended touring trips.