Not a completely simple answer. I have tried three models. It is possible to keep building, you shouldn't have to stop cool, clean, and reflux. But if you have a bad result that could be what you had to do. I remember this thread where someone took a course and they where tought to build stalagmites of brass, rising up say a foot or more, to learn the appropriate heat control to build a stack that didn't slump. Flux will keep running off in this method and it gets scooped back into place with the rod.
Another paradigm is to work webs in at the quarters, or less, and then capture the fillet in-between like filling a bowl. A variant is to place the fillet on one side, and just keep rotating the joint to place more material in the pocket on one side.
I work mostly with silver and for the most part cause those fillets to simply place themselves with surface tension and they have hardly any radius at all.