Maybe need to do some fuzzy math:
1) Taking CG this yr, is a "real" savings of 20K x 15%? (what will CG rate be in the future vs 0% this yr) = 3K? What will you do with the 3K.....spend/invest?
2)Doing Roth conversion costs you now at 15% bracket and saves you later at
bracket? Generally there is only a minimal advantage if you withdraw later at the same tax bracket.
conclusion: .........it depends.......the only thing known for sure is that LTCG rate will be 0% this yr. Seems like a slight bias toward the stock unless you think you will in a higher bracket when you withdraw from TIRA.?