Whilst I have designed and built several transconductance phono stages, with great results, the GTi is in fact "the opposite" as it's a transimpedance stage, ie current in voltage out. As such it presents a near short circuit to the cartridge and all conventional matters about loading etc are obsolete. An adjunct of this is that gain is in effect set by the cartridge itself, it's internal resistance to be specific.
Non of this has any bearing on suitability for use with a Rega arm and I believe you are probably thinking of compatibility with balanced input phono stages there. I made one for a fishy in New York a few months ago actually (an Arkless 640P in fact) and although USA customers cannot try before they buy I will export to USA but obviously there will be customs charges etc.