CM 12 + gapps flashed but no google service and now can't flash anything. topic

Using Odin/towelroot/twrp I was able to flash CM12 on my tab pro 8.4 but after flashing gapps none of the google apps actually work - they all say that google play service is required. I tried flashing different gapps packages and also directly installing just the google play services APK.

I done a full wipe then attempted to reflash CM12 but the flash would just hang on "skipping md5 verification" or whatever it says and nothing is ever shown on the progress bar. Only way of getting out is to hold the power button and turn the tablet off which of course breaks it. Luckily I can use odin to flash the stock firmware and have my tablet working again. However I was very impressed with the new android and would really like to run it. Is there a way to flash CM12 with odin?

Thanks.