Read thru some topics, look at the offered pix (of which you've posted none in support of your 8Sq In 1% figure) the vast majority of small soft areas on decks and transoms is significantly worse, not a little, a lot worse, then expected.
I'd rather be wrong and have you replace a transom that might (and might is about all you can say) last a season or 2 then have you do a bandaid, less then substantial, repair and let you be wrong that its safe.
Add in the amount of resistance you put up to using an appropriate sized OB on 1 of your boats, the constant reminder that your a broke student, and absolute refusal to losten to the advice you are given, repeatedly, and you'll likely do whatever it is you want, how you want, so proceed how you deem correct.
Doesnt make any of the offered advice incorrect or over reaching to suggest the transom needs to be replaced.
Good luck, wear a PFD and boat safely.
Is the handicapped young man you want to take boating a strong swimmer?