I prefer the RIVA 901 cone with my 510 cartos. It is shorter, and gives a bit more airflow.
The 510 cone should work, but fits more snugly. It also Leaves little room left for your mouth, and a drip tip generally addresses this problem.
I think ce2 cartos are just a hair skinnier than the Boge. And fit the 510 cone just fine.
The RIVA carto deluxe kit comes with a 510 length cone, but has a slightly larger bore, like the 901 cone. (still follow me?)
I can make some carto kits mañana.
I don't know anything about st Patricks day,,, but I got some goodies on the way for April. As well as a couple prototypes, of some new products. I can't really say much beyond that.
Oh... Clearomizers and Giantomizers too! Sometime soon, I hope...