nineyman, you are, quite honestly, on a wild goose chase.
I repeat what I said in the thread Anne referred to: "Most Lowland Scots in the 15th, 16th or 17th centuries probably regarded Highlanders as dangerous savages and would have been horrified at any suggestion that they were connected in any way to a Highland clan."
The surname Shanks, according to G F Black's The Surnames of Scotland is of territorial origin, from Midlothian. It is very definitely Lowland and to the best of my knowledge and belief there is no Shanks tartan.
sancti is absolutely right. If you want to wear tartan, pick a pattern you like and get one with it. There are no laws about entitlement to wear a tartan, and no-one will be in the least concerned whether or not you have any connection to the clan, family, district or organisation whose tartan you are wearing, assuming they can actually name it, which is doubtful.
If you do have ancestresses with a Highland surname, or the surname of a Lowland or Border family which has adopted a tartan along with the trappings of a clan, you can use those names to narrow down your choice from among the thousands of available tartans.
Just don't, please, do what I once saw: a man dressed from head to ankle in Dress MacMillan tartan: kilt, waistcoat, jacket, plaid*, bonnet, tie and matching socks. The only things he was wearing that weren't Dress MacMillan were his shirt and shoes; in my opinion that was, to put it mildly, overdoing it.
*For the benefit of anyone who thinks that the word 'plaid' means 'checked (or even chequered) cloth': in Scotland, it doesn't. The cloth is called tartan. A plaid is a garment made of tartan. It can be either a huge voluminous affair like a cloak, such as is worn by a piper in full regalia, or a much smaller garment, like a short cloak, worn over a jacket.