I was wondering what the policy for using "Wincustomize.com" when designing a skin, theme, wall?

I have a couple of Idea's for the above mentioned, but do not want to step out of line.
Also if done' should they be presented for consideration before posting for download to ensure that there is a cohesion between, the quality of the design, look, feel and being bug free along with the desired impression of the site presented to it's members and possible future members?

Anyway, is there a document on the site that I have overlooked or any un-written rule on this subject?

I know I think to much

But always best to ask before hand then find out otherwise after, or put others in awkward positions of not wanting to seemingly insult but also being in a position where the choice was not there to begin with.