As Dave Tooley said, in 1000 yard BR, there are basically no stock dimensions. If it is a light gun, it must weigh no more than 17 lbs (NBRSA). That will put some limits on your stock in that it can't unlimited in size.
100 / 200 yard benchrest does have strict rules about stock width, angle of the butt, etc. If you are using a 13.5 twist barrel then by design, you are limiting yourself to shooting light bullets; up to around 68 grains or so. So by design you are building toward a 100 / 200 yard rifle. I would go back and re-think the stock and go with one of the good short range benchrest stocks. That way, you will not have to modify the shape of the stock. Modifying the stock you have chosen may be more involved than just changing the toe angle. Most 1000 yard stocks are built with a weight limit of 17 pounds in mind so you may have to remove weight from it to get down to the short range weight. Further, I would think long and hard about the finished weight of the rifle. If you build a 10.5 pound 6mm rifle, you can shoot it in the sporter class, the light varmint class, and even the heavy varmint class. If your finished rifle weighs over 10.5 lbs but not more than 13.5 pounds, you can only shoot it in the heavy varmint class. If it weighs over 13.5 lbs, you can only shoot in the unlimited class.
Joe
ps. You can search and find LOTS of info on building a good short range rifle. Most of the posts will explain it much better than I have.