The pressure release valve is on the right of the inlet on the solenoid valve and has been tested.

Going full pressure sounds interesting, was going to use bungee return anyway so that's not a problem. Yes it's a standard paintball bottle and weighs 650g, does appear to be a bit overkill now you've said it. My only reservations with FP was sourcing fittings and being a 4 bar the ram needs to be mounted and be able to pivot at both ends (unless someone can figure out a different way it could work).

Sam from what I remember the old Loki was about 490x490x80 (with lots of 20mm HDPE) so new one is taller but slimmer (with a lighter but less beefy chassis)