Bottom aeration, bubblers, might seem counter intuitive in that the shallower the water the less effective they become and the more diffusers you will need. The deeper the diffuser the more surface area that is affected. Try to understand the bottom contour of your pond - you could try to map it but that can be hard to do or expensive to pay for if you are on a budget. I used a couple of pieces of 3/4" PVC glued together marked in one foot increments and tested the depth at random places all over the pond using a paddle boat. I can't map using that but I was able to tell that the majority of the ponds is pretty deep and the bank goes from shallow to deep pretty fast, and I only have one area of the pond that has any shallow bank to any extent. Based on that I went with bottom diffusion. If you find most of the pond is actually shallow - in the 5' - 6' range as you noted than surface aeration is probably your best bet.

As Esshup noted, it is important how close electricity is to your pond. You can aerate with the compressor a long way from the pump but the further the pump from the pond the more discharge pressure will be required, and therefore bigger and more expensive compressor you will need so sizing becomes important. People have differing opinions on if it is better to run long air lines or run long electricity - long being subjective. I chose to run electricity - I think anytime you can get water or power to somewhere you don't have it you have added value. I had to run 230' and it cost me around $/ft for rental ditcher, 10 ga 3/1 romex, and conduit. I was able to do it myself so that save a lot. It could be cheaper if you run 2/1 romex but if you are already running power using 3/1 romex gives you the option of another circuit in the future.

I am just throwing out what I did and my thought process in the event that it is helpful. There are a number of folks on here who have designed and built their own system as you propose. I am not very familiar with surface aeration since my pond called for bottom aeration. It can be a ton of work but I made the commitment a couple of years ago after buying a place with a badly neglected pond and things are now turning the corner and we are really enjoying having a pond. The folks at Pond Boss and this forum are a great resource.