Well you came to the right place on this one. I'd check your local regulations or where you plan to fish though. Most places will not allow you to fish during the spawn. I'm not a big fan of going after fish during the spawn in the first place. It's also probably not the best time to try and do it either. Spawning fish tend to focus on the spawn and not so much eating. Some fish that nest will bite, but it's often a 'protect the nest' reaction rather than eating. Prespawn you will have the biggest females around coming in, but you will still have very cold water to deal with.
First thing let me ask you a couple of questions. Where do you plan to do this at? Is this a lake or river? Up here where I live we have a huge lake population that are river spawners. We also have some of the most liberal seasons around, and we are not allowed to fish during the spawn. In fact it's the only time we can't fish for them.
Just as a point of information, I do fly fish for Walleye a lot. I do pretty well at it also. I get them all Summer long. I get them in the Spring. I get them in the Fall. Every season has advantages and disadvantages, but you can still get Walleye fly fishing.
A bunch of flies that I have found that work on Walleye.