Hi !
The way the A4 is organised, I would advise using one kit per pattern. Once you load a kit, write a sequence, and save your kit and pattern, the kit and patterns are linked together, and recalling a pattern will load the associated kit.
Recalling a kit does NOT recall the associated pattern, however.
So it’s pattern -> kit
Hope this makes sense. I usually do A1 - kit 1, A2 - kit 2 etc… If i want to use the same kit for patterns A1 and A2, I would copy kit 1 to kit 2, and assign them to their respective patterns, for the sake of clarity and sanity. That’s just me though.
The cool thing about this organization is that, once you have filled a number of patterns, each with their own kit, you can then load different kits to the same pattern, and get some VERY unexpected results. Keeping your kits and patterns linked in a logical way means that you can easily go back to the original kit a pattern was written with 
Cheers