What we set at VIP as max. sizes is 20mm thick (perpendicular to mould line), 35mm long (a little more including tab actually) and 35mm wide. If there are separate parts they should be sprued, by preference to the main figure, to avoid extra work for the caster. Perhaps it's an idea to adapt this here too. A reason to set a max size is to make sure they all fit in one mould and the ideal casting conditions are the same for all of them.
By the way, don't forget to tell the caster we want the greens back (made that mistake once).