It is far from being a sure-science but there seems to be a 10-20% success rate when following published procedures.
10 to 20 % seems pretty good.
Much better than waiting for an accidental graft hybrid.
Since the Chimera is fully 100 % type A plus Type B, ( tetraploid ? ) that is probably a better % than hybridisation via pollination and seed growing.
(You would get a 50/50 hybrid by crossing, some of those won't be useful cultivars )
This method in the research paper seems to be using seedlings, which are still a way off fruiting ?
I wonder if you could shoot tip approach graft from mature flowering plants or cuttings for faster flowering Chimeras ?
I couldn't find the research papers re Solanum Chimeras either.