Short answer: no. no source found during my own string experiements...
Long answer: I once wanted to do something similar with a CM set and a CL set for an experiment too. I ended up buying both sets as normal.
Fellow UU brother Bazmaz had a thread (and video) a few months ago in which he gave the spec for using fluorocarbon fishing leader, and how it compared to Worth strings. maybe you can get a small spool of the leader in the optional gauge, and just add that to an existing set for your test?
Not sure it will be much cheaper than buying a second package (which is enough for 2 sets) of Worth strings @ ~ $12-15 depending which set.
Other folks have also detailed using fluorocarbon fishing leader and what gauges too here in the forum over time. The thread I remember most had posts from OldePhart (Jon), and he gave the string gauges for light/medium/heavy sets on all scale lengths.