Perch Fishing Deep Down

[okflyfisher]

I would suggest a very fast sinking line and 3 or 4 feet of tippet w/ a size 8 clouser(or 2 or 3) weighted with bead chain.
Yellow perch are the only fish I have caught 3 at a time on a fly rod. Although I was fishing in water only 8 to 12 feet deep

In water that deep it would be easier from a float tube or boat so you can cast out and paddle away from you cast as you let enough line out to reach bottom plus enough line to give you a low enough angle of retreive or drift (guess 3 times depth plus) so you are not pulling it off bottom in your targeted gravel area.

Good hunting