Doug, you might try the commercially available feeders!

I've yet to see one of the simple inverted red bottle feeders (with red cap and tray and yellow flower) fail to attract multiple hummingbirds. They've been in use at two of my parents' homes as well as my mother-in-law's house and cottage, plus my wife's aunt's place. They work every time.

Then again, maybe those Mexican hummingbirds are a lot fussier.