In my experience there are some GREAT benefits to Premium and one of the chief of those would be buyer-attraction, but I would not count on coming across leads for listings or off-market deals as a result of your premium membership. 

Highly recommend that you find some comps with ADUs on the market and see how their ADUs are designed.

So, make sure EVERYTHING the sales rep tells you, or agrees to, is in writing signed by you and the builder's designated broker (not the sales rep).

I worked with a designer/architect to come up with two ways of accomplish the goal.

Very few homes go on sale in this area and this is a very unique listing for anything of this quality/design features.

Might make it slightly more attractive.   

I own a structural engineering firm and co-own a design-build firm.

So, it's very important to pick areas to work in where you feel comfortable being in and also comfortable working with the type of clientele the community attracts.

Being from DC, I expect your design would be wind controlling. 

A study released August 24 by personal finance website WalletHub ranks Austin among the 10 most attractive real estate markets in the U.S.