I would think is there a dominant stripe that stands out more than others? A yellow would be more effective than a red. I'd also look at what is being hidden in the pleat as when you are swishing a lighter stripe hidden in the pleat is exposed for dramatic effect. I don't think that there is really a set(t) answer to your question. For example the recent US Army tartan that USAK made has two yellow stripes very close together. To me this might be too busy looking, but if you look at the recent postings it did work. Check out http://www.xmarksthescot.com/forum/showthread.php?t=23840's thread in regarding this forementioned tartan, his thoughts and the replies. It is a very interesting read. When all is said and done it probably is wise to listen to your kilt makers opinion.