I have the Vampire, similar size. Not yet flown. Although it has retracts, I will be hand launching and landing without the gear down. Spoke to a visitor to our scale day, he was flying same model, he stated that there is not enough power to take off on grass. Also,changing retracts will not help the mtg in foam, which, IMO, would be the weakness. Having said that, the visiting Vampire flew very well. Hope this helps.
Stuart