How's the battery life compared to blu spark? (Without overclocking ofcourse)
As said by OP, he tries to keep Kernel close to stock. So if you don't modify any kernel setting, battery life is identical to stock oos kernel. There are lots of features to play with the kernel . You need to install boeffla-config app for this. You may want to check default presets if you are scared to try things or simply don't know what you are doing. So you can get better battery life based on that.
The special thing about bluespark is bluespark governor and fiops io scheduler which in my opinion is optimized for balanced profile with more focus on battery.
By no means, I intend to compare these kernels because both are great. This has been my observation and I may be wrong. :fingers-crossed: