Tried Negrillo de Almoguera last season against 6 other blacks and its production and resistance to cracking were outstanding. Fruits are large (10-24 oz.) and perfect.
http://www.secret-seedcartel.com/car...o-de-almoguera
Grosse Verte Rose was also super productive and crackless and about a week earlier than Negrillo de Almoguera. Over half the fruits exceeded one pound with the largest 29 oz.
http://www.secret-seedcartel.com/car...sse-verte-rose
I've tried dozens of black varieties since 2010 and these are the most noteworthy so far. According to your description, it sounds like you might be interested in a smaller tomato, though, whereas I prefer the larger slicers.
kath