When I was printing B/W in the darkroom, there was a lot less agonising over "blown" highlights in the print than there seems to be now. We cheerfully accepted that certain areas in the clouds would essentially be paper-white, for example. And we would always try to ensure that specular highlights printed to paper-white in order for the image to "pop" as it should. So the idea of deliberately degrading your highlights by pulling everything down to below 245 or whatever is anathema to me.
So my digital B/W prints also have pure paper-white areas in them, and this does not bother me at all. In fact it is the way I like it, just as I like to lose my deep shadow areas to pure black. This being the case, the colour of the matte is very important indeed, as if it is white there will be a direct comparison with the whites in the print. The crucial aspect IMO is to ensure that the matt white is always warmer than the print white. That way the whites in the print will look clean and "pop". The other way around looks dreadful - a cooler, brighter white in the matte makes the print highlights look grey and degraded. So I tend to use very light cream mattes to complement my B/W prints on the Harman Warmtone gloss paper.
John