First let me say I am not familiar with the barrel sizes of a Reedy and you don't mention whether you are going to build from scratch or using a pre or partially shaped blank. Here is what I do with my two Gillespie patterns. When I made the patterns I made them the same as the original rifles, big clunky barrels and all. I did this so I could use them for those wanting close replicas of an original. I ran into problems having so much wood to remove when I or someone else wanted to use a smaller "A" or "B" profile barrel. To solve this problem Mark Weader (my stock man) made an undersized stylus for his duplicating machine. When making a stock for a rifle intended to be used with a smaller than original barrel he uses the undersized stylus. The end result is that the whole stock is made undersized to match proportions with the undersized barrel. This works great for me. It might work well for you if you can find someone to duplicated a Reedy pattern with an undersized stylus. (before you ask, I don't think Mark has a Reedy pattern but I am not 100% sure of that).
Dennis