Hi Gary.
In the last pic the three on the right were pressure cast and the 4 on the left were not. The resin I'm using at the moment is very good for degassing without the need for pressure.
The slight size difference is to do with the mould used for each batch rather than a presure / no pressure thing.
I make my own silicone moulds and the narrower ones are designed for slimline pens and slightly slimmer to reduce wasting resin.