I'm taking a tailoring class (watch out, world!) and we had a lengthy discussion about pre-shrinking all the components of a tailored garment. I've searched here and found some comments about pre-shrinking hair canvas, lining, stablizer, etc. but can't find any mention, here or in TAOK, about pre-shrinking the actual wool tartan fabric.

The idea is to run your raw fabric through whatever cleaning method you would use on the finished garment, prior to cutting and sewing. This eliminates the initial shrinkage, however minor it might be. One method for making wool "needle ready" is to steam it, either with a dedicated steamer or by shooting steam at it from your conventional iron (from a distance of an inch or so, never actually touching the material with the iron surface).

Seems to make a lot of sense to me, considering the amount of steam that a kilt will see during construction and subsequent "freshening" by the wearer. You can tell if the fabric has actually shrunk any by carefully measuring and basting around a 4-inch square prior to steaming, then measuring that square after steaming. Even a sixteenth inch of shrinkage could prove significant when you are measuring your taper in 1/32nds.

Or do you consider yardage from the top-name mills to arrive needle-ready? The prospect of steaming 4 yards of DW material is daunting, and I wouldn't want to tackle it needlessly. OTOH, I wouldn't want to suffer the consequences if I should have done it, and didn't.

Here are a few (unsatisfactory) references to the topic:
Tailor and Tailoring (doesn't mention the fabric itself, but pre-shrinks the notions)
Off The Cuff (not a method I would use with kilting fabric!)