I just bought a Savox 1210sg for my Veles 29, but it only came with an assortment of plastic arms, none of which are the correct size to replace the Spectrum S603 that is in the boat now. The arm on the Spectrum won?t fit the Savox either. I want to put an aluminum arm on it, but I don?t know the correct size to get. I have a 25T arm, but the mounting holes are too tall. Does anybody know what the correct mm I need to get? Thanks!