Last year I started their Rumpler C.IV (a superb kit) last year and found I needed something to get the large internal lozenge decal to snuggle down. I used Microsol and Microset with no ill effects and they settled down nicely over the fine stitch detail.
I also used the same solutions on the instrument and radio decals. Some of these were tiny and no problems were noticed. In fact I found their decals to be quite tough. They are however, very glossy so will need a matt or satin clear coat after.
Other people may have different experiences.
Good luck with your build, you definitely will not regret buying any WNW kit.