There's a few vendors who produce quality Jango armor, but I understand the cost factor being a detriment. I'd alternatively suggest using Sintra plastic to produce your plates. I did that to make my armor masters for my custom-scaled Montross chest armor. While I could have used the sintra pieces, I took it a step further and made molds to do fiberglass cold cast.
That being said, it's a bit of extra work to get them formed right. I know a lot of folks in the mando mercs who use sintra for their armor, but either don't actually do much forming of the plates or do a simple curve and call it a day. Jango's, on the other hand, have a very unique curvature that I don't realistically see you pulling off with EVA. It's not that you CAN'T get those curves heated into the EVA, it's just when you're going to wear it mounted on a flak vest, the soft nature of thin EVA will warp an alter.
Honestly, most places you can get sintra for pretty cheap. The technical name for it is "foamed PVC," and I've usually been able to get a 4' x 8' sheet for about $35 on average. If you have a local plastics place nearby, even better. Seriously, it's really easy to work with, dirt cheap and you'll have more than enough to work with even if you screw up. For making the curves, the most complicated ones was for the pectoral, to which I made a "form" using floral foam from a craft store. I built a block, drew out the plate, and sculpted away. It really took about under an hour to get it where I wanted, but I then put a thin coat of bondo to seal it up and further smooth it. Once I was happy with it, using a pillow, I placed the sintra plate (cut out from the armor template), heated it up until it was very pliable and "floppy." Once that happens, I take the floral foam form, and pressed down onto the soft sintra plate, holding it down until it cools. You may have to repeat it a couple of times, but you can't argue w/ the results
Here's my montross build thread.
https://www.therpf.com/showthread.php?t=226607&highlight=montross