Marla, that all sounds good, but I'll let the experts make comments. Gosh! I love this design!!! What did you decide about the water spouts on the raised beam? If you wrote about this already, I'm sorry I missed it. Will they be more of the trickle splash or a medium splash?
I have a Dolphin M500. Mine definitely has a cord, but it's not a big deal at all. Nick and I LOVE, LOVE, LOVE the robot (our Rosie). We are amazed at how well she works. The fine (corrugated) filters get up fine, fine dirt and sand (which I didn't think we had much). And so far, she's had no trouble with any leaves including pine needles and oak leaves larger than my hand. The only time she doesn't clean as well is when old Suz doesn't put her in the pool! Lol!!! Last summer, I swam with a Polaris in the pool. I really didn't think too much about it, but swimming in my pool without that is awesome!!!! I also like not having a pump running burning more energy. My analogy is to the microwave. I couldn't imagine why in the world I needed that kind of appliance. I wouldn't live without one now. I feel the same about Rosie. Thank goodness Patrick more or less told me to get one. (Just kidding, sort of - he was very enthusiastic about it, though!)
Oh, BTW, I bought our robot at a place on 1960 nearing 45. I'm sure you could find one closer to you. Wendy bought her own, too, but I'm not sure where. I didn't do a big price search since I decided at the last minute to switch to a robot. Just google Maytronics and you can find local retailers and I'm sure online ones as well.
You've got a terrific plan. Your backyard is going to be fabulous!!!
Suz.