If your spindles have a chamfer sticking down like my spindles on my 430, put the JD blades on top that have the 3/4" hole over the chamfer and put a set of blades with a 5/8" hole on the bottom to fit the bolts. DC blades are 5/8" in case you need that size. You can get them at your local Lesco dealer or DC dealer. Not sure what other brands have a 5/8" holed blade. This will work though.
Does your JD deck have a chamfer on the spindles? If so, read the above post I made. Just bolt the blades on in a + formation and torque them down good. Unless you hit something solid, they will stay in that formation.
You are it seems, looking for something that is not there. Grass cutting ain't easy most of the time. Some of the time during dry periods it is easier. But in rainy times triple cutting the grass can be normal. Lets face it. Sometimes the grass business suxs. And sometimes it doesn't sux as bad. lol. Only thing you can do is raise the blades higher and cut more often. During rainy times. The profit margin takes a hit.