I would try 1/4 oz. Other than that they are looking great, stick to it and you will be as good as the pros here. Oh and investing in a good airbrush is a very good idea.
Very well done. My only recommendation would be to move the front hook hangers back a little on the next batch because it looks like the hook would be able to catch the line.
If you want to do any supertuning in reels I would recommend checking out the TT forum Fishing Forum and just ask all the questions you feel like. Just make sure to use the search feature if it is a basic question as most forum members don't like it when the same topic is brought up more times than it needs to be. I don't do much supertuning or upgrading myself as of now, so I can't really say anything else than what the ones before me.
How long did you wait before painting/finishing? You might have not given the air time to escape before you finished them. I don't think that heat treating them would be such a good idea if you did'nt heat cure them. One thing that you could do to find out if you have air trying to escape is to take a recently poured and cured bait and submerging it in water and see how many bubbles come to the surface and then compare it to another raw bait that is a week old or so and see if there is a differance. Thats all I can think of but i'm sure someone that is more knowlegable than me on this subject will chim in.
Rofish, could you go in depth about this x location? Is it the bottom hook hanger and the tow eye, rear hook hanger that makes up this x? Please explain. The cone shaped belly weight sounds like a really good idea.