Hey Everyone.. Sorry for the delay.. I got a wonderful head cold this week and it put me out of commission for 3 days

feeling better finally today so got a chance to get back at it....
Need some advice and evaluation please on the progress and next steps to take.. I have done transom repair but never on stringers... Here are some pics from what I did today.
I am hoping I can get some opinions and advice as to what I should be doing next?? Can I purchase the plywood for the transom and stringers.... Get them cut to shape and coated with resin so they will be ready to install? Then do I grind, grind and more grind? What should I be grinding? Can I leave the channels in where the old stringers sat so I have a reference for the new ones?
Please help where you can to keep me moving forward
Thanks all!
Dezi