I have the Laser with a Saito 72 and it hovers at a bit over half stick which is more like 3/4 throttle. I don't know about hovering at 1/3 throttle............must have some weird expo in the throttle setting.

My brother has the same plane with a Saito 91 and it is a bit overkill but not too much. We both have an alternate set of landing gear to cope with the ground clearance needed.

I think a 46 will not hover it satisfactorily. In any case, you will probably have minimal power to pull out. I don't know how much your pipe will add though.

Whatever you choose, please think about replacing the stock motor mount. It WILL start to pull from the firewall after some time without some sort of reinforcement.

Marcus