As a T1 diabetic who uses a CGMS ... I see no effects from vaping on my BG levels.

vape wont effect your glucose level...
the only side effect was some people had very small chance sensitive to PG,which can cause muscle cramp and tingling feel,which is not really a big problem if that don't bother you.
if you dint feel anything then nothing worry about.
nicotine wise,it have same cigarette effect,heart pump faster,dizziness if consume too much.

i start with doing both smoke and vape too.
just force yourself to stop smoke,dont buy cig,throw away your lighter.
at 1st week after i stop smoking,im still craving for cig,that's normal,all you need to do is to force yourself,its not that hard trust me,just vape your favorite juice.
after 3 week,i bet you won't craving for cig anymore,altho sometime im still think of smoking cig,but i can just ignore that by vaping easily.
it's been months now i had quit smoking,feel so great. my room is finally smell so good now,no more smelly cig odor...
trust yourself as i trusted in you that you can do it. welcome to vape family,smoking is dead vape is the future...