A really nice tube on the datasheet, but after testing it seems there is a LOT of margin in the specs as you can see in the table below.
The current at the 150V/-1.5V bias has a range between 12 and 33mA, discounting the 45mA outlier. That is almost a factor of 3. The rp and µ are also all over the place.
This tube is a disaster to try and get matched pairs as the spread is so large that even with 35 tubes I had to compromise a lot to make pairs rather than "matched pairs". Specs look nice on paper, but this tube is a pain in the ass to get matching if you nly order 4-6 pieces.