Looking at another thread I saw everyone's advice regarding refrigerating cake batter - the overwhelming impression I got was that recipes using baking powder only instead of baking soda had a better chance of success.  I have to bake the cake found at http://www.sprinklebakes.com/2016/04/black-velvet-nebula-cake.html, and I will be unable to bake the full recipe at the same time; in fact,I will have to bake each layer separately and will have to refrigerate some batter while some is baking. The recipe calls for both baking powder and baking soda - can anyone recommend any recipe changes to help?

me, I would divide the recipe into the closest correct amount for the pan size and only mix that up at a time --  if necessary add the extra dab of batter to the next batch or bake it off ---

I typically divide the batter by the eggs -- if there's four eggs you can half it or quarter it -- if there's three you can obviously go by thirds --

baking powder often has baking soda in it -- I myself would not divise a new formula -- I would just mix up the right amount of batter --

do a search for the following chart for amounts of batter for the different size pans

wilton wedding cake data chart

Thx.  (Your little doggie always makes me smile.)

me too he's the best -- thank you!

then actually the only other thing you  need is the yield of one recipe so you know which way to go with everything -- a recipe is usually anywhere from 5 to 8 cups of batter or if you are not in the u.s. it goes in the other measurements that make me crazy 

Baking powder contains baking soda (which reacts with acidic ingredients such as cocoa and buttermilk). If you're concerned about the leavening power of baking soda, I suggest you use a lesser amount of acidic ingredients by substituting some regular milk for the buttermilk (half milk, half buttermilk, or even better - all milk). 

I've never made that recipe, but it's similar to the chocolate cake recipe I made in my retail shop. We made large quantities of batter, then baked off some for immediate use, and refrigerated the rest; then baked as needed during the following week. 

I know home bakers have much to say about loss of leavening power; but in my experience I've not found much difference between a batter that's baked immediately and one that's been refrigerated several days and then baked.

i have muffins that i would keep the batter fridged -- but for cake i do get anxious if it's not baked off right away or at least within reason but it could just be me being hyper but still it worked for me 

Thx everybody!  I'm not quite Cake Wrecks, but I'll keep my day job!