The current Kodak Reversal process needs some modifications to process the R100 successfully. The movie labs don't say what the changes are, but if not modified, the result is very ugly brown stains. The Official Foma process uses a bleach that is a bit more agressive than the Current Kodak formula.
Thank you very much Charles, Lab offered an +1 push development and asked me to 1/2 stop compensation. Do you think that solves the staining problem ? I think I will use dr5 but 3 times more expensive !
Yellow/Brown stain usually indicates poor bleaching, and cmacd123 mentions the stronger Foma bleach. AFAIK the Foma bleach uses KMnO4 and an acid, but I don't know what Kodak uses. Since KMnO4 is trivial to obtain anywhere and the same is true for Sulfuric Acid, it should be fairly easy to mix such a bleach yourself.
You may want to talk with Niagara Custom Lab. http://www.niagaracustomlab.com/ I believe they have the process figured out. you will be shipping it internationally anyway so Canada vs the US is not a big deal.
If you are using a lab you need to ask them what film they normally process.
For the first film Id bracket in 1/2 stops.
For critical shots bracket in 1/3 stops.
Used to use colour transparency for weddings you need to incident meter every set up and every time clouds moved for less than 5% not perfect the bracket covered the 5%.
Most pro teams will be shooting on 5222 cine negative
I had the impression that the OP was using 16mm Movie film to shoot movies. If 35mm B&W slides then yes forget the Kodak reversal process which is for Movie film only.
For movies, using the negative positive method is far less critical for exposure and even processing. trick is there are very few movie labs who will actually make a film print these days. Most want to take the images into "That other realm".