Finally purchased a Control Ring Mount Adapter EF-EOS R

I don't own a mirrorless camera body yet.
I am waiting for a possible sale or rebate first.
I have my brand-new Canon Control Ring Mount Adapter EF-EOS R ready for use.
It seems to be a popular item that is out of stock everywhere locally.
I may pay the extra $600 and get the R5 or R5 C. Still undecided. People claim the R5C eats batteries.
Maybe the R to avoid the R5 ibis heat and extra expense.
Done researching different models and purchased the R5 body.