I'm using HiTec hs-55s. I have stripped one but that was do to an unfortunate incident involving Olympic style floor exercise down the landing strip with my Bipe upon landing...other than that, no problems with these servos. My biggest complaint with this plane is its roll rate...it snaps like caca and rolls are S L O W!! I thought about making the ailerons bigger but I'm not sure that would help...Anyway, I think the .25 would do your Bipe well.
Mike