Hilde, here's another perspective.
I applaud your efforts to do crosses as I do others, but most of the folks that I know pay little to no attention at all concerning tomato genes and dominance, recessiveness, except when using a PL for the maternal plant when the other parent is an RL, so one can tell if the cross took.
What most folks seem to do is to choose two varieties that have characteristics that they'd like to see combined in some way, into ultimately one offspring.
So that means saving seeds from thje initial F1 hybrid, planting out as many as you can from those F2 seeds, making selections from one or more plants whose fruits and performance please you, planting out the F3 seed, etc.
That is, they don't sit down and look at genes and try to predict what they might get based on the parents they've selected.
It's kind of like my foray into breeding daylilies when I'd go out in the AM and cross pretty by pretty. Or frangrant by fragrant.
Don't get me wong now, a knowledge of tomato genes , at least of the more common ones, is good to know, but there's so much more that isn't known, one example being the genes involved with gold/red bicolors.