Hi there! May I start by saying, your Wallace & Gromit model is fantastic! (http://www.wallaceandgromit.com/creations/view/11934) You've managed to really show off their personalities well! For starters, Aardman tend to stick with around 8-9" tall for the majority of their characters, with the obvious acceptions of Gromit, Fluffles, Shaun .etc. Now for the eyes. I infact encountered the same problem a few years back. Personally, I feel as if I never found the correct size, but in all honesty, I have always seen fault in my models, so I may have been wrong. From behind the scenes videos, hours of reading books and advice from other users on here, this is all the information I have gathered in the past few years: Aardman use between 5mm and 6mm diameter glass beads and apply enamel paint for the pupils by placing the bead on a cocktail stick and securing the other end in the drill. They then spin the drill at a low speed and use a very thin paintbrush to get a perfect circle. Here is a model using 6mm beads: http://www.wallaceandgromit.com/creations/view/5953
I hope this helps you, as you seem quite the promising young sculptor!
Anyways, kind regards,
Josh 