There are ways to tell but again they are not simple ones as you are aware.
“Can be differentiated from A. cataphractus by the lateral body plates of the caudal peduncle meeting above and below (except the last one), whereas in A. cataphractus the last four or five pairs are separated. A. spinosissimusalso has a broader, spinier, post cleithral process ('humeral process').”
But good luck with that if you don’t have one of each to compare!
And of course Spinosissmusis supposed to grow an inch bigger, which won’t help you until fully grown and even then is no guarantee.
if you can post some photos, the group can assist and advise (help guess!).
As for sp2, you will hardly ever, if ever, find one! An import no one has identified previously which could even have been thought to be a hybrid.