Try to find a 150 class BT in WA would be the hardest part.... No matter how much you scouted..... And for the WT nut... Have you ever seen them during the rut?
? Not the smartest deer in woods would you say.... But what do you think is gonna happen when you only get it once a year for a maybe a few weeks... I'd die trying as well..... 
A 150+ blacktail is huge. However, the odds of finding a 150+ typical blacktail in WA is a far cry better than finding an equivalent (size ratio) typical whitetail or mulie in WA.
A 150+ typical blacktail is roughly on par with a 185+ typical whitetail. In the B&C there are 30 blacktail bucks of this caliber that have been taken in WA. there is only one typical whitetail of this caliber (from WA) in B&C.
As for mule deer. A 150+ typical blacktail is roughly on par with a 200+ typical mule deer. In B&C there are only four of those that have been entered from Washington.
Whitetail bucks are more visible during the rut but it is very rare that I see them in the almost completely oblivious state which I often see with Mulies. I have heard that blacktail rut behavior/vulnerability is similar to whitetail.