According to Fitday PC Software:

1 small Potato Skin -- 8g - 1g = 7g Net
1 med. Potato Skin -- 10g - 1g = 9g Net
1 long Potato Skin -- 16g - 2g = 14g Net
1 large Potato Skin -- 15g - 2g = 13g Net

1 small Potato --

16g - 1g = 15g Net (w.o Peel)
20g - 2g = 18g Net (w. Peel)

1 med. Potato --

21g - 1g = 20g Net (w.o Peel)
26g - 3g = 23g Net (w. Peel)

1 long Potato --

34g - 2g = 32g Net (w.o Peel)
43g - 4g = 39g Net (w. Peel)

1 large Potato --

31g - 2g = 29g Net (w.o Peel)
39g - 4g = 35g Net (w. Peel)

I think there's some overlap. I.E. the "skin" figures probably include the peel and some of the innards that may adhere to it...

small = 1-3/4" (D) - 2-1/4" (D)
med. = 2-1/4" (D) - 3" (D)
long = 2-1/3" (D) x 4-3/4" (L)
large = 3" (D) - 4-1/4" (D)

Baked Potato w.o Peel (per ounce) -- 6g - 0g = 6g Net
Baked Potato w. Peel (per ounce) -- 6g - 1g = 5g Net
Baked Potato Skin (per ounce) -- 10g - 1g = 9g Net