I should think a tenor in C would be better to get first. They are much more widely used in recorder ensembles. In fact, I think voice flutes are most often used to play transverse flute music on recorder. If you were going to be playing such music with a “specialist group” (it’s hard to know what you mean by this), I would think they’d more likely want an actual flute.
Also, you’d have a larger choice of instruments with tenor. Seems to me that voice flutes are so specialized that they are all high-end instruments. I don’t think I’ve ever seen a mid-priced one.
