How do you decide when you have enough research results to write a paper and to which journal you submit the paper
JCR is part of the ISI Science Citation Index family of databases, which is not especially reliable in its measurement of computer science impact. See for instance this report from Informatics Europe which specifically warns against using ISI databases to measure the impact of computer scientists.

In any case, if you want your papers to get attention from other computer scientists, publication in selective conferences is still the way to go. We can argue whether it should be, but that's what it is. Some conferences (e.g. SIGGRAPH) count as a journal directly (their proceedings are published as a special issue of a journal), others (e.g. FOCS/STOC/SODA) expect their authors to later turn the same material into an expanded and more polished journal paper, but the conference is to a large extent how to signal other researchers that your work is worth paying attention to. If you're not familiar with the conferences in the area, choosing one sponsored by ACM or IEEE over one that isn't is a good rule of thumb, as is choosing one that calls itself a "symposium" over one that calls itself a "workshop".

However, that doesn't mean that you have to partition your work into least publishable units as you describe your coworkers doing, and it also doesn't mean that saving up multiple small results into a single paper is a good way of making your papers stronger. It's certainly possible to publish papers like that but to my mind the better ones are often the ones that have a single strong main result, perhaps with additional results on the side not to strengthen the paper but rather to provide more complete coverage of its subject.