The layout kinda reminds me of DE_Dust 2. The CTs start near A as well, but between the 2 bombsites.
Here's a suggestion: Time yourself with your knife out, how much time in average it takes you to get from the CT spawn to B. Do the same for the Ts and make sure its less time for the CTs then the Ts. And with enough seconds for the Cts to mount a defense, and enough room to not get nade spammed upon their arrival.