kinda depends what wind strength (and water temperature) you intend to go out in. Personally I dislike the 'locked flat' feeling of a trimaran and really enjoy the heeling and the challenge of sailing a miniature keelboat to its best. So if I were you I would try without the outriggers first.
HOWEVER! I only sail in light to moderate wind conditions in relatively flat water and the water here in Auckland is never excruciatingly cold (in the event that I take an unexpected ducking).
I sail an Adventure and it is a somewhat different sailing proposition than a fully loaded Oasis - basically you have a lot more weight and resistance to overcome with an Oasis with 2 on board so for a given wind speed the sailing performance will be less than for an Adventure. Given this fact the sailing performance in light winds may feel rather pedestrian - which may tempt you to go out in stronger breezes so as to get a more enjoyable sailing experience.
2-up the Oasis has substantially more ballast than the Adventure so it should be able to cope perfectly OK with greater wind strengths but of course this depends on exactly how strong the wind is, exactly how well the crew can sail the boat, and, I guess, exactly what the implications of getting it wrong are. It is all about risk profile: if t'wife has a sense of humour then she might be OK about getting her hair wet unexpectedly; if not then you might be willing to give her the required listening to in the event that you tip her in; on the other hand if the pair of you are likely to freeze to death or get eaten by sharks that is altogether a different set of risks (or maybe it is not
Subject to the above observations I would give it a go w/o stabilisers (betcha don't still have them on your bike!) and take it gently as you learn the ropes before you make up your mind. You should be able to single-hand it quite effectively too if you add some ballast up front.