Ok. So I knew that was going to happen, Honestly, I knew the pattern on the right would never survive I did, so why do it? Because it just might have been ok! ok!
Making patterns needs a number of skills, one is understanding if your pattern is up to the job. It needs to be able to get out of the plaster. I've seen glass patterns bound in plaster as there is no where to grip, and of course undercuts are the bane. But they mustn't be too fragile either. That's why the cone style worked well to create a nice mould, whilst the other broke. BUT! I had already printed the next pattern, ready for this failure. That is one of the true benefits of 3D printing for mould making, the ability to easily prototype and develop your pattern until it works.
When they dry. I'll see if they make anything worth seeing! These are to go on top of a mountain, might make some which can hang on a tree as well - slightly larger.