Post a pic of the brake MC, that will tell if your metal lines are metric threaded gland nuts or not.
I have a vague recollection that all the RRC callipers have a metric thread for the brake hose at the lower end, but the upper end of the hoses can be metric or imperial because there is a difference in parts catalogues for metric or imperial brake hoses.
You need to get professional advice with this.
cheers, DL

