Adding an aftermarket Hood Scoop help needed

Is the bottom of the scoop flanged with bolt holes? Does it take a flat gasket or the u shaped channel around the perimeter? A pic would be good. It can be a tedious process to get a scoop to sit and fit nice. I make a template of the scoop, measure and mark a centerline and the bolt holes. Not all scoops I've had in my hands are actually symmetrical so I use the centerline. Then use the template to mark the centerlines on the front and rear edges of the scoop. Then I cut the template back to the scoop perimeter and tape it down trace it out on the hood with a sharpie based on the centerline marks. If I move or retrace I use a different color sharpie. On that I would relieve the center so the sides sit flat on the hood and then build/fill in the sides adjacent to the center ridge. That would be easier then trying to rework the entire perimeter. It would involve some cloth and resin because you just can't hang a chunk of filler off the edge of a panel and expect it to stay there if doing it to the scoop side. Or, some metal work on the hood side.
I have used 1/4 inch doubled sided attachment tape in place of the gaskets. Available in black or clear. Some gaskets are pretty crappy and the tape can be done nice and neat and barely noticeable. One time around outboard the bolts . Second time around inboard the bolts. Also, I usually use nylok nuts. I've had some crack from trying to tighten down a split washer. There's other ways, just my approach without seeing all the parts IMHO.