IMO the three already in are good given the other stuff there.
Make the new ones a little taller - say 6 ft. Add about 3 or 4 pieces of pvc sticking out of the top to get it up to about 10 feet of total height. If you do that and put them where the red markers are how deep will the water be?
I always want some structure to cover from bottom in a deep area to within 3 ft of the surface (unless it is a swimming area). Most of the year (Oct to May/June) fish will use deep water structure. With aeration they will use it all year. Bigger fish like to be able to go up and down the water column near structure to feed and or escape.
If you look at this picture, you can see darker water at the base of the big logs, that will be 18-20' at full pool, the 3 pvc bushes that i placed are on the flat area that is shallow water in this picture. They stop at the edge of the deep cut.
The angled log between the concrete cylinder and the pvc bushes is now placed on the drop off at the left of the picture.
I have a lot of free 5 gal buckets and was given a lot of scrap pvc the other day. It looks like I have enough supplies to make 6-8 more trees. I have 3" and 2" to make the trunks that range from 6' to 12' tall and enough 3/8" and 1/2" for the branches on the 2" trunks and 3/4" and 1" for branches on the 3" trunks.
Here is what am thinking:
This would come from the front corner, down into the deepest cut of the pond, passing by the ends of 3 large (24"-36" diameter 15-25' long) submerged logs that are on the slope, also passing by the end of the line of pvc bushes. The line will rise up and end at the mouth of the cut between the island and the north bank in 8'-10' of water.
This deep water line of trees should tie in all the shallow-to-deep routes in the larger end of the pond.
