Schwarzbier--grain sub for Caramunich III--help please

Hey all--

Just about to brew and I see that I bought Caramunich I for my Schwarzbier, not Caramunich III as specified in the recipe.

Can I sub in a portion of Extra Dark Crystal or Special B, both of which I have on hand? Any ideas on proportions?

Below is the original recipe (from BYO)

Medieval Cloister Schwarzbier
(5 gallons, all grain)
OG = 1.048 FG = 1.012
SRM = 30 IBU = 24 ABV = ~ 4.6%

Ingredients

5.5 lbs. Pils malt (<2° L)
1.0 lbs. Munich malt (10° L)
1.0 lbs. Munich malt (20° L)
1.0 lb. Briess CaraPils (1.5° L)
1.0 lbs. caramel malt (60° L) or Weyermann CaraMunich
III (53-60° L)
2 oz. Weyermann dehusked Carafa II (375-450° L)
5.4 AAU Hallertauer (bittering) (1.2 oz. of 4.5% alpha acid)
0.5 oz. German noble hops, such as Hallertauer (flavor)
0.5 oz. German noble hops, such as Hallertauer (aroma)
Wyeast 2206 (Bavarian Lager) or White Labs WLP830
(German Lager) yeast
1 cup corn sugar (for bottling)

I would just go with what you have. There is not a huge diff between 1 & 3 in a dark beer.
I would be more concerned about the amount of Carafa 2. That amount will give you a nice red beer. When making a Swartz I use 200g(7oz) each of dehusked carafa and choc malt to get a black beer.

Thanks...I did use dehusked Carafa II, if that makes a difference. Northern Brewer calls it "ideal for Schwartzbier." Thanks so much for writing back.

Yes the dehusked carafa 2 is exactly what you want for a Schwarzbier. I just would have used about 10oz if it was the only roasted malt in the recipe.
It will still be a nice beer but imo closer to a Dunkel than a Schwarz, although a true Dunkel needs more munich and less pils malt.