Since the thread is still open (but somewhat wandering off track) I thought I would report on my dewinterizing experience - March 15th. The car has been stored since Nov 15th. Reason for storing was travel plus I dislike driving it in the almost constant rain in Vancouver and worsening drivers skills (not mine).
I have had motorcycles and cars and boats that are stored for up to 6 months a year and have done so for more than 50 years. Due to lack of garage space I store some vehicles in a storage area that has no electrical outlet so requires battery removal or disconnect.
My procedure is to use fuel stabilizer, fill with high octane fuel, wash/wax, remove negative battery lead, cover. Realizing the doors etc will not open without battery and not wanting to use the manual key method, I simply left the frunk popped open 1 inch so I could access the frunk to reattach the battery lead.
Dewinterizing the C8: Have the fob handy. Reattaching the negative battery lead may setoff the theft alarm so once the battery is connected push the fob Open and Close button and that shuts off the alarm. Everything now works engine started as new. It takes a few minutes for clocks to adjust but everything came back (radio channels, Nav, seat memory) as it was the day it was parked.