I dive the Lake Pleasant spillway a lot, myself! Hook up with El Mar Dive Center in Mesa. One of their regulars owns a huge pontoon boat, The Diver Down, fitted for several divers. They go out regularly to Tech Island at Lake Pleasant which has great depth and decent viz. Great group of divers, too. With my schedule I’ve only been able to make it out once, so fun to be around the tech divers but plenty of rec divers on that boat, too.