my batch sparge with strike water raising grist to 168F.You might be able to get a few more points by fly sparging. Takes a little more time than batch sparging, but if you're decocting, what's a few more minutes. Besides it gives you more time to RDWHAHB and become one with your system/process!
I started out fly sparging, and would never go back. Batch sparging IMO is optimal...less time,hassle,and if done right you will be in the high 80's efficiency at worst. Performing the hochkurz pushed me into the 90's, and I'm more Han happy with that percentage efficiency.