Consistency on the machines foam is produced on has a maximum of 0.75mm diameter change through a 10,000M batch, which is just about the best I could find and much better than any FBR available.
The pro foam will be rod. I will also make it a different coloured blue to differenciate them.
I will investigate what my supplier can do in regards to Grain size, the actual material used is EVA foam and I believe this can be manipulated a fair bit from what I have seen on the market. Take pools noodles for example.
As for bonding agents, I haven't run into any problems with using a similar method to Chaos Blades. I use a low temp gun, drop some glue in first into the dart down the hole and then embed the weight, with another layer on the top with a slight excess when the cap is pushed on to make some of the glue seep out the side then smooth it off with your fingers. I have tried 7-8 brands of hot glue and I can say the best I've come across is plain clear el cheapo 2 dollar store glue. Officeworks glue is also good, but the guns they slot into are far to high temp and burn holes in everything I've tried.
Using this method for darts I take to wars with a BBBB has worked flawlessly, very few weights and tips have come off even after 2-3 wars. I think nerfing should be limited to this range otherwise it will simply turn into a milsim fest.
The problem is glueing a porous surface to a non-porous i.e Foam to Metal, Foam to plastic. I'll have to look around for a cheap option to do this. Epoxy does but it is rather expensive, unless in bucket form where I have seen it pretty cheap. I'm just thinking out of the box here.
Diameter is going to be the main problem as everyone has his own preference to material. I'm even of thinking of swapping factories to try to get smaller MOQ's to do both Brass and PETG. Brass is a great material it's downside is it's cost and availability in some areas. Perhaps even developing our own custom material could be an option to although this would easily get messy when nesting breeches etc.