I would be surprised if you need flaperons to land it. Very few RC planes ¨need¨ flaps or flaperons at all. Especially if its a 3D plane it will have low wing loading and should float in. Generally flaperon mixes are used for certain 3D manuevers rather than for landing.

If you do use the mixes practice with them high up but I dont think you will need them. They will probably be more of a hassle/danger for landing rather than beneficial.