I say Kaddish for several niftarim and I also say for their yahrzeit after the first year.
The shayla is how to keep them in mind. I keep a list on me with their names and yahrzeits so I know how long to say Kaddish for them. I keep a list on my computer to know when their yahrzeit takes place.
I have seen others keep this list in front of them as they say Kaddish, but I wonder if that is necessary. I have quite along list.
The easiest way for me would be: when I initially add them to my list, say their name and that that I am saying Kaddish for them until a specific date.
For the yahrzeits, it would easiest at the start of each week to say their name and their yahrzeit and that I will be saying Kaddish for them on their yahrzeit that week.
While saying the kaddish, one should focus on the words of kaddish, and not on any names that one wishes to have in mind.
The effect of kaddish for the niftar does not come from thinking about the name, but from saying kaddish in their merit.
Therefore, I think that your method of “dedicating” the kaddish that you will be saying in advance, at the beginning of the week, the day, or whenevery you wish, is fine.