75 KZ 400 Special , Coil Change

So I've already been on here before and let everybody know that I am very new to this. I have a 1975 KZ400S the previous owner said it was running it is a Kickstart only. And there is a Dyna S electronic ignition system installed in it but since they don't really make them to fit this bike it was obviously retrofitted. I need to replace the coils I think and I'm wondering how to do this and I'm going back through to check all the wiring to make sure it's hooked up right but I don't have a schematic for the Dyna S because I didn't install it and I can't find any more information from the previous owner. Need help. I bought a cheap Chinese $35 coil because I knew it was four ohms but I don't know if I should go with the dynatech and I don't know what the Dyna S electronic system is putting off because I know you want to buy the coils that are at least bigger than your electronic system so you don't burn the coils. I've done a lot of research and I just feel like I don't have enough information and maybe I'm missing something

If I am not mistaken in the past (not sure about now) there were Dynatek systems made for in line twos, certainly for the Honda 350 and 360.  Not sure what system you have, are there any markings on them any numbers of any kind? Not knowing just what system is on the bike is hard to determine what coils are needed. In my own mind I can see how a system built for an in line 4 with wasted spark could work on a twin, but not necessarily on all twins.

You are correct, there was never a Dyna S designed specifically for the Kz400, so whatever you have is a custom setup.  Photos would help to show if the setup is viable.  A photo of the rotor is necessary too.  Then we can help you get it working once we know the mechanical setup is sound.

And you are correct that a 4-ohm coil is what you want.  The Kz400 originally came with a 4-ohm coil, and the Dyna S works well with a 4-ohm coil.

So the first step is to probably mount the new coil and plug wires since you will need that regardless of what ignition system you use.
A photo of that will help us spot any problems that text can't describe.

Back when KZ400.com forum was still a thing there was a guy selling an electronic ignition for the KZ400s. I can't remember who it was but there are a couple of people i recognize from those days over here so maybe they will chime in...
edit: did a quick search and it looks like Charlie's Place was offering an electronic ignition from DynaS components.  KZ400 electronic ignition upgrade