You could just use industrial strength adhesive backed 2" velcro tape to attach the tent canvas / vinyl .. sew one side of the velcro to the tent section and stick the other to the camper tub side and use an ally 90* angle frame fitted to the roof under side with one side of the velcro tape stuck to it, Attach the tent section top edge with velcro sewn to it, to the ally angle ..
No need for sail tracks and to have the Keeder track edging, I did a home built camper using heavy duty Silver / white poly tarp for the tent section that had all seems held together with 2" industrial velcro Never had any troubles with leaks in wet weather in 12 years of use .. Each side / end etc could be taken off to make repairs or alter if needed ..