What you got from the other maker was not BS, once fired brass from an other chamber is one of the biggest wastes of money and accuracy I can think of!
Brass that fits your chamber so perfectly that it's just moving a couple thou and springing back after each fire and size cycle brings a level of consistency you will not achieve with brass that has formed to another chamber unless it's a smaller chamber really either by luck or actually building a fire forming barrel.
Match reamers means what ever they guy who spec'ed it thinks match is.
If you have a tight Sammi chamber and you buy brass out of a sloppy Sammi chamber your hooched, again!
I have only one Saami reamer, I really don't like them cause they are marginal for everything, that's the point, I use very specific reamers for specific reasons. IF I got it my pumpkin to use only once fired brass I'd have a reamer made based on what showed up for brass and what my sizer would do with it, more than likely add a little to the base and put the neck to .004 clearance and bring the throat down a little from most Sammi prints. I'd then headspace it a little longer so everything would be happy, happy but that'll never happen cause it's so much easier and cheaper to use new quality brass the first time.