Looks great, are the hotswaps glued or friction fit? They aren't designed to be put in a hole so I wonder about their tolerances if friction. If they have a nice mould burr round the edge that's probably good for this.
As to the price yes brass is expensive - an interesting choice for a prototype so I'm really glad it worked! Given how solid it is have you thought about using aluminium for the 65%? Obviously not going to be as heavy as brass but could be heavy enough. If not stainless steel is plenty heavy and a quick glance at scrap values suggests it's only 20% of the price of brass, though that would increase the machining time so maybe not good if you're paying for that too.
Not surprised your beautiful wire bending took hours, your soldering speed will improve 
Those hotswaps are pressed in. My first intention was to use adhesive to locks them, but then i found out if i machined those pockets 0,025-0,03mm under, the plastic housing will be compressed and stay there beautifully. So no need for adhesive. But if the hotswaps fall apart after a while - but i don’t think that they will, you can always use adhesive like epoxy to glue them in.
My workshop that i’m working only and only machining brass, so other type of material is not allowed
. But if i can, i would love to try to make a solid stainless steel one. I’ll pass on aluminum because everyone else is working on aluminum, and of course i can’t compete with that.
The 65% i estimate that it would need about 16kg of raw brass material, and it would be ~7kg when finished. This is just a quick sketch.
