Hi James,
When I tried building on XO-1.75, it had taken several hours. I didn't know repeated builds could have been that fast. I will try doing repeated builds once again and if the build time comes under 1 hour, that's good for me . So, Using XO-4 seems like the best and safest option for me right now.
@list : Thank you all very much for your candid suggestions. I appreciate it.
-Basanta