As I too am a beginning kilt maker (very novice), please take my advice as such....

I wouldn't think doubling it would be the way to go...

That sounds like it would be very difficult to keep the two layers perfectly flat and what not.

How thin is the material? If it is less than 10-11 oz., I would think perhaps you should use it for something else.... If you can easily see through it, it is probably too thin....

OTOH, I made my first kilt from 11 oz. material, and it worked out pretty well. First, if you don't have Barb T.'s book, get it - there are some great things to know about kilt construction in general. Secondly, you will need a hem, something over 3 inches would be good (it will make the kilt hang better). Thirdly, a hidden pleat in the front apron would be good for more weight, and you also may want to make extra-deep pleats at the first pleat at the apron and for the inverse pleat at the underapron. Lastly, if you have about six inches of material for the outer apron edges, that will add some weight as well when you finish them off.

Other than that, I have no idea, my brain is now empty.

Good luck, it is a very rewarding thing to put on a kilt you constructed for yourself.....