Bear in mind the OS .40LA is on the low end of the power range for .40-.46 size engines, but it is also the lightest. A really light 3D plane would work, as would any .25 size plane. The 40LA isn't that much heavier than a .25/.28/.32 size engine so a .25 size plane would give you a speedy combination.

For a 3D plane, you need to check the size and weight. If you see them flying it with a Saito .72 4-stroke, it'll be too heavy. As I recall, the Magic can be flown with a .32 although most of us in the US use a .46. The Thunder Tiger Lazy Tiger P-51 would be one I think would be good for a .40LA.

If you don't mind Coroplast, get a 24" square and make yourself a Pizza Box Flier. It's more fun per square inch than anything else you'll find and a .40 LA will be perfect.