RWJ,

I just went through this with a friend while getting ready to stock his offhand gun.  You basically have two choices...

ONE:  attend a match, and "try on" as many rifles as possible.  If you find one that fits you and your shooting position, take measurements of length of pull, drop at the comb and heel of the stock, any cast on or off, and have your stockmaker try to fit you up.

TWO:  get a "pattern stock", either by having one made, or using an old stock, and modify it with bondo, etc., until it fits you and your shooting position...then send it off to be duplicated.   

There's a lot of trial and error involved in this method, but it results in a stock fit specifically to you and your shooting style.  The only other option is to get a replacement schuetzen-style stock from one of several sources, and then make your position fit the stock.

There are a LOT of variables to consider, including but not limited to your physique, stance/position, whether you plan to shoot iron sights or scope (or both), and strictly offhand or bench (or both).

Hope this helps more than confuses...

Greg

rwjshooter;
               The two prong buttplate fits over the arm--IMO most shooters building rifles today seem to like the single prong buttplate--its kind of a happy medium at it will fit the arm or the shoulder.  Some men with big arms [not me] have a problem with the two-prong buttplate.       leadball