Could you extend the boom of your wife's trike? Sometimes the chain doesn't allow enough slack to extend the boom very far unless the trike has an extra long chain and a "gobbler", a device that takes up the extra slack. Then you can position the boom both way in and way out. If the chain won't allow enough boom extension take the chain off the front chain ring and stick it out. You can at least get an idea of the fit that way even if you can't ride it.
I suggest going to a specialty trike shop if possible and trying out many trikes; they vary a great deal in size, fit and feel. I have a Catrike Trail and an ICE Adventure and they are quite different to each other---the Trail sits considerably lower and has the pedals higher compared to the seat than the ICE which has a higher seat and lower pedals. A person could hate the one and love the other.
Anyway, I think there is something out there that will satisfy you.
Last edited by boilermaker1; 10-26-20 at 11:31 AM.