I'm trying to remove the blades but the nut on both blades won't budge. I sprayed them both with WD40 but still not happening. I got the mower up on jack stands so that I could at least sharpen the blades but they are in bad shape and still cut rough. I didn't want to try and loosen the nuts while it was up on the stands because I feared pulling too hard would knock the mower off the stands.

Problem too is that even when I roll the mower up on a ramp, each ramp is directly under each nut so even though I have the ground clearance, the ramps are in the way of getting an impact wrench in there. Any ideas? Maybe a ratchet and socket with an extension and a breaker-bar?

Use a block of wood to wedge between the deck and blade, this will hold the blade still while you remove it, the breaker bar and perhaps a cheater bar is a good option. Use caution, and either remove the battery connection(+), or spark plug to ensure the engine will not start.