I think you might be able to squeeze a little bit more speed using -n 0x4000000000000 -k 8192. If you saved your 1TB bloom filter using -S, you can re-use it with the different -n and -k values. You have another 0.5 TB ram available, have you tried -n 0x4000000000000 -k 12000 so you can max out your RAM? Even then, you'll run out of money or die before 135 is found.
I will try with -n 0x4000000000000 -k 8192, but for every different command I need to wait a couple of hours for the bloom filter to fill the RAM.
I tried also with all the 1.5T RAM but the speed is considerably slower because on a dual socket system, each CPU typically has its own memory controller and dedicated memory channels. This architecture is known as NUMA. Latency increases and bandwidth decreases when a CPU accesses the memory attached to the other CPU.
So I'm running 2 separate keyhunt apps with these commands : numactl --cpunodebind=0 --membind=0 ./keyhunt0 -m bsgs -f 135.txt etc etc (1T RAM)
and numactl --cpunodebind=1 --membind=1 ./keyhunt1 -m bsgs -f 135 etc... (512GB RAM).
You are right, 135 is very hard but better to try my luck on random than going sequentially specially on these high ranges puzzles.