I’m on a Mac and just use the Finder to burn my images - Right click on the file and select “Burn Disk Image <filename> to Disc…”. This works well with the .iso images for njvc’s set. Not sure why you would want to use the MKV if you are burning to a physical BD disc. NJVC has two options for you - all 25GB discs or some 50GB discs. Make sure you have the appropriately sized blank discs of course. I chose to go the 25GB route so I needed 10 blank 25GB BD discs.
Nothing to lose and another possible coaster to gain. Will attempt this right now. It can’t be that easy… 😃