Nice ! Well, i think i won't try your kernel since my battery is not really in a good state and overclocking would make it worst, but do you think you could add OTG support in the kernel ? It seems the material and rom are OTG ready ('drivers' etc) but the kernel isn't
There are some otg settings in kernel config:
But even when compiling kernel with all of them enabled (except CONFIG_USB_OTG_WHITELIST) OTG doesn't work. So it wont be that easy
As for battery life, it almost the same when idle as on stock, base clock is almost the same, differs only few MHz from stock. It uses more when You need it and that is obvious as it's overclocked over 400MHz from base clock.