Well, if you don't know how to paint your plane, I wouldn't expect the local fender man to know either.

Yea, Ty has it. Problem I have is humidity level. Takes forever for stuff to dry when the humidity is 80%. A low temp oven with a dehumidifier would be nice.

Having some experience in this process the short answer is yes, baking it caused the grief. Lawuer by nature is virtually NEVER dry. It dries and shrinks for years. Hence the reason it is so repairable. The problem is in fact that this process occurs. When you bake it, the Urethane clear kicks, and seals off, then the solvents in the laquer want to escape and have no path to do that, ESPECIALLY on a solid wood model like a speed plane. On a built up plane the solvents can find an escape path through the fuse or wing and out the leadouts etc. Still baking is not a good idea.
Of course, there is another option, that being that after every layer of differing material, you go bake it. so you build up the substrate of laquer, then bake it, do the glass , then bake it, color coats , bake it, clear, and bake it. Were it me, and I felt it neccessary, I would start with a bake cycle of say 150 degrees, then for each step, cut the temp by 10 degrees . In composites this is how Post curing is done. you bake it to a temp higher than it will see in its real life and then it is stabilized for any temp under that.

Now for the clears, spot clears are really no different than overall clears after a period of 24 hours or so. The real attribute to spot and repair clears is that they tack off faster. IOW, they are dust free much sooner than overall clears and this allows the painter to cycle cars through the booth faster, ( or in most cases these jobs are painted on the floor or under a prep station where dust intrusion is a problem)
Baking doesnt really create a stronger finish long term it pretty much just accelerates the reaching of that point. Its a chemical reaction and as long as all  chemicals are together in the proper balance, it is going to cure to the same hardness.
I dont really like to bake clear unless its a deadline thing personally. I dont like to reduce my window to polish that way. For those who havent, rubbing and polishing urethane clears is best accomplished after about 24 hours, and before 36 to 48 hours has passed.

I have a stunt plane painted with acrylic lacquer with a two-part clearcoat over it.  It has some black places that still get bumpy a year after I painted the plane when it sits in the sun awhile.  The bumps go away when I sand with 2000 paper and buff, but I have started to sand through the clearcoat in places.  Mark explained the solvent trapping to me and added the wisdom that "black lacquer never dries."  I am looking at pastel colors for the next dog.

Once again, incompatability of materials. How many times has this come up? With the same answer? Once again, matched finishing systems, Mark has explained this thoroughly in another thread. I am not a painter by trade but was taught by a professional. That's how I know. Where on the can of nitrate does it say " spray car paint on top " ? 

I like solid wood for the smaller racing planes and have quit using dope on them.  The procedure now is water base poly clear sanded.  Then if I want clear finish I go to the clear coats.  Of course sometimes it takes several coats to get it like I want it.   Mucho easier with colors before the clear.  DOC Holliday