Best advice I got here: Try before you buy.
Are there some not-too-far away places that do lessons/ demos?
Excuse for a road trip

?
I'm new, too.
Bit taller, lighter than your wife, but am really happy with a 2nd hand 9"10 X 29" board (~160L volume).
NOT what I'd have picked unless I'd tried one.
More stable than I'd thought.
Also, hated an 11".
Felt like a plank by comparison (I wasn't in surf).
Also, just bought a carbon, lightweight paddle


Best thing- makes a big difference to me (slightly weedy arms).
ALSO, try talking to someone over the phone.
Again, I might have got the wrong paddle if I'd just bought online without advice from someone who sells more than one type.
Good time to buy as many SUP schools getting rid of their summer boards to buy for next season.
$650-700.