I just thought there would be some sort of approval process, or something. By whom, I'm not really sure. I know it it outside Lord Lyon's jurisdiction. But I figured I would have to "request" it.
Well,

Just from what little I know from talking with you about how rare the Wage surname seems to be and how little history you or anyone else has been able to find on it, I'm going to assume that there is no "cheif of the name" out there; no "Lord Wage of that Ilk" to report to on such matters.

The decision to formally adopt a family tartan for the name would be his or her perogative, if such a person existed.

For instance, the Hardin family recently adopted Wilsons No. 1 as their family tartan. The decision was made by Barry Hardin, Baron of Cowdenknowes. As fas as I know he is the only titled member of the Hardin family. As such, I believe all he did was inform the STA that he had adopted this tartan for the Hardin name. They did have cloth woven and are now wearing it.

Since you don't have this kind of authority who is able to speak for the entire surname, there is no one's blessing you really need to ask, aside from your own family members who may share an interest with you in the tartan.

Aye,
Matt