That's a great idea! I just took a closer look at the version from EntertainmentEarth and I agree with you, that it looks different. The mold from 2005's R4-G9 might indeed be better to use.
Have you already gotten an extra droid for your custom? R4-G9 has become harder too find here in Germany, but it's not too bad. I recently got a
droid collection and I got some doubles - especially R2-units (like everyone else does apparently). lol
Have you already asked folks on Facebook as well? There are groups for everything and I remember
Rasputin37/
Wraithnine from back in the days (2008). He was also member here, made
some YouTube videos and is an Astromech expert located in the United Kingdom.