The pure nickel will be higher tension.
Yes, the actual tension numbers appear to support this idea.
Boomers (hex-core) 45-65-85-105 = 186.5 lbs.
Balanced Nickels 44-60-80-106 = 184.2 lbs.
Boomers (hex-core) 45-60-80-105 = 174.2 lbs.
Round Core Boomers 45-65-85-105 = 173.4 lbs.
Balanced Nickels 40-56-76-101 = 172.3 lbs.