I just had a Dometic slide topper installed on my slide (93 1/2" flange-to-flange) and happy thus far with the product and mounting.
With any slide topper manufacture first confirm the model and proper size (important) of slide topper for your specific slide width (flag-to-flange)....., each manufacture has a sizing chart.
The slide topper sizing chart may not reflect the actual fabric width but the overall roller length (cap-to-cap). Also, in many cases the mounting hardware is a separate order and not included with the topper fabric roll.
Depending on the brand/model slide topper, confirm that the anti-billow hardware is included with the mounting hardware.
Also, some Jayco model's already have the slide topper fabric 'mounting rail' installed on the sidewall (sometimes part of the gutter rail), otherwise insure it's included with the slide topper order.
Bob