I have the Pro translite already , and luckily signed by George Gomez, and the pen he signed with is a silver thin texta style pen.
The great thing about autographed translites, is that when the machine is turned off, you can see the signature, and when the machine gets turned on, and the fluro light kicks in, the signature dissapears, which means u get the best of both worlds.
Its difficult to get brand new translites for late model Sterns autographed by GG, SR or JB, unless someone does u a favour ofcourse.  

I reckon it adds value to your machine having a signed translite, cause it just gives u that extra little bit of personality from the original game designer, and u have something in your machine that 99 percent of other people dont have. Something different anyway, and a little bit of a extra mod so to speak.

Premium translites are not available at this stage, but down the track I will get notified when GS allows them to be sold without the pinball machine attached. The Pro translite for Avengers looks amazing when lit up, so I reckon the Premium will look great as well.
A Pro translite next to a Premium translite will look excellent, espescially if both were signed. Stay tuned.