I made my feeder ring 2' x 4'. I wish that I would have made it 4'x4'. But any size will work.
I used 90 degree elbows on the corners and glued
it together with pvc glue. Then drilled a hole
in one side, put in an eye bolt to tie a rope on.
I siliconed around the eye bolt so that the pvc pipe wouldn't take on water.

With regard to my 4" manuel feeder. The fish suck the chum'd feed out of the 1/4" holes. I fill the feeder with Aqua Max 1/4" pellets and yes, the pellets turn to mush. The mush can easily be eaten by all sizes of fish.

When I first saw this type feeder, I posted it on this board to see if anyone else had ever tried one. A guy wrote in and said that his daddy n law had one and that he had actually gone under water with scuba gear and watched the fish feed.
All types of fish will feed on this type feeder.
blue gill, catfish, carp, etc.

It's cheap to make and it works.