I just got seeds for Hahms Gelbe Topftomate in trade so I can't offer any insights, but if this is the same variety as yours, maybe we can compare notes later in the season.
I'm going to tentatively put it on my list for this year's Winter Indoor Tomato Trial and grow it in containers in a relatively shady (i.e. less sun than ideal) spot this growing season.
Here's an excerpt from Tatiana's tomato base:
"(Tatiana's) Very early, 50-60 days, det., 6" tall cute mini-dwarf plants with rugose regular foliage, high yield of yellow cherry fruit for such a small plant, very good mild flavor, great for growing under lights in winter."