Sorry, for such a late response, but I don't log in to the forums much anymore. I don't have any DIY for this and it's been a very long time since I did it, so I can't give you exact details, but I can give you the general process:

1. Find a source for 12v constant power. You can use an "add-a-fuse" kit to tap into an appropriate source at the fuse panel, or you can run a (fused) power wire all the way from the battery. Make sure you use a suitable gauge of wire and fuse for the power window circuit.

2. Get a "momentary on" and off switch. This can be a push button, toggle, rocker, whatever. Just make sure that it's mom.on-off. This way the windows can only be rolled up/down while pressing/holding the override switch unless the ignition is on. If you really wanted to, you could use a regular on-off switch, but that would make it so that you'd have to remember to turn the switch off to undo the bypass. I suppose if you really wanted to you could do a permanent bypass by just not using a switch at all.

3. Use a relay. Unless your chosen switch can handle a pretty high current, it is recommended to use a relay to supply the power triggered by your switch. You can source positive power for both the switch and relay from the constant 12v wire that you already set up in step 1. If you're not sure how to wire up a standard relay, I'll let you google it. There are a few different common approaches that work.

4. Hook your triggered override power to the 12V-IGN power wire in the power window harness. In my '97 (and most other year models, I believe) it is the black wire with white stripe. Depending on what modifications if any you've already made (such as a DIY power window switch assembly), you'll have to determine the best method for splicing in for your install. It wouldn't be a bad idea to wire in a diode that prevents the override power from backfeeding into the 12V-IGN circuit, but if you don't know how to do that I'm not going to get into it here. I can't recall whether or not I even bothered to do it on my install.