David (#4), I believe 'cross grain' was/is a paper surface. I used a lot of DuPont paper for enlargements in Canada in the 1960s, initially in my high school darkroom and later in a small commercial studio I worked part time for. At the latter we used many paper surfaces that were truly beautiful, especially when toned, but are no longer available and for which information has largely vanished in the mists of time.
I recall all these papers came with very long and greatly detailed data sheets- how I wish now I had kept some of those, but alas, they were all sent off with the garbage, nothing was recycled in those days. Even more sad, the studio was bulldozed in the late 1970s to make way for an office block - apparently a lot of the original photo and darkroom equipment was still in the building and was mashed into rubble for removal in trucks. Wanton destruction, but back then it's how it was, for so many things we now regret.
Nostalgia for things now long past aside, I recall printing with DuPont filters was somewhat "primitive" and one had to work to force any sort of decent contrast from the negatives, but photography was different in those days, overexposure of negatives was the norm, developing in Kodak DK50 or DK60a or some of the more hyperactive, by today's milder standards, film developers from Kodak, Ansco et al, tended to push the middle tones into the upper levels of high contrast. Very long exposures and careful development were required to produce pleasant skin tones and the soft focus effect then so beloved of middle aged and older sitters. For all these efforts, I still have,in my family home in Canada, a couple of hundred original prints I made then, and when I look at them now I marvel at the quality we were able to get. But with 4xt negatives, why ever not?
I agree with GregW's (#2) suggestion that awty should put this paper aside for now and print with newer material. I also would do this, with such old and rare (1947? The year I was born, so it must be super good paper, hah!) and Iwill go a little further and say, keep all the old paper you bought for a year or so, in cool and dry conditions, and return to it when you have more expertise in enlarging techniques. With good negatives and a little care, you will be amazed at the quality of the prints you can make with it.
No fog, what a blessing...