[bower]

I nearly passed over this cross for 2015, but I'm really glad I didn't.
Zolotoe Serdtse has a lot of interesting traits besides its growth habit and high fruit/shoot ratio.
Beta is an interesting trait to work with, although the tight linkage with growth habit mostly defeats the original purpose of the cross - to make some different colours/shapes/textures of fruit with the same growth habit. The semi-determinate segregant was of course a Beta orange, and entirely similar to the mother fruit in every way except shape and size. Slightly smaller and earlier, mostly round, and very firm and slow ripening.
Firmness and slow ripening can be a useful trait, it has its place as also its limits.
Unfortunately both ZS and her Beta semideterminate offspring suffered serious quality issues in 2015, associated with low light levels and record cold temperatures through July. Both of them had about half their fruit unmarketable quality due to uneven ripening and some grey wall - disorders of potassium metabolism associated with those adverse conditions and with other causes of K deficiency. Other tomato growers in our area had the same problem with some varieties, as I did too with some but not all of the OP's and others. So... it has raised a lot of questions - unanswered - about the genetics of K metabolism, and also about the genes for 'firmness' which seem to be really stacked in ZS, and dominant and/or penetrant in subsequent generations.