You have come to the right place friend. You'll find a wealth of information here and a ton of great people to explain any questions you might have about boba fett, jango fett, zam wesell, prop building, painting and just about anything else related to costuming.
Howdy there and welcome to TDH! As others have said, you've come to the right place if you're looking for a professional .
I gotta say your son is lucky to be part of a father-son---team right there. I've seen a few pop up here and there ... and I can just say is just so darn lucky to be a part of it!
I'm working on it... Here are some pics of our helmets (Jangos not finished)... Also, if you wanna upgrade from the Rubies, I can give ya some tips on making a complete childs Boba costume for just under $200. Actually, it'd be cheaper for you since you already have a helmet, and you could cut the belts off of the Rubies and use those too. Just send me a PM if you need any info.
The TK in the pic isn't me BTW, its my cousin. My Jango won't be finished until around April or May. I'm currently doing a repaint on the kids jet pack to match the SE theme. The jet pack is also included in that $200 that I mentioned. Super easy stuff to do.
I can hold your hand for it... lol... I replied to your PM, BTW. I'll walk you through everything as you go. First thing is to get started prepping your sons Rubies helmet.
The only thing that you will need to buy for it is a new visor which can be had for $10 from http://t-visor.com/
The visor is already sized for the Rubies/DP helmets... So you shouldn't have to do anything to it for fitting.
Also you could pick up some small bottles of testors paint at like wal-mart for a little over a dollar, and add some topical damage to that puppy for more detail. Thats if you dont want to repaint the sucker.Cheap, but can work wonders for appearance. T-visor.com has excellent visors, I have one in my helmet.