IIRC, you have a TC. I lost my choke cable long ago (and when I had my TC with Strombergs, I never needed the choke at all, but I lived in New Orleans which is very warm) so I can't say if it was a stranded cable. My heater cable is a solid wire. Since neither of your knobs have any graphics, they won't look so odd but if you're looking for something more original (and nicer looking) than a plain generic cable, I think I found them here:
https://www.angloparts.com/pdf_catalogues/Tools_accessories_catalogue.pdf look on page 48 with knob 083.798 for the choke cable and on page 76, there is a knob kit that includes the heater knob 083.791. The heater knob is listed as 083.793 so they may sell individual knobs. These knobs go with the cables around page 48. Be sure to look over this catalog. They have a lot of interesting things. I have never ordered anything from them so I can't vouch for their shipping.
It's been a long time since I put my motor in but I think it might be better to run the cables before you put your motor in in case you want to tie them down somewhere. I think even with the motor in, it shouldn't be too difficult to do that but it might be a little easier before the motor is in.