if I may suggest a current balun with an SO-239, to connect to the coax output of the tuner. It should have wing nut terminals to hook to your line. Then the balun will push equal currents into the twin lead and your antenna. I mostly use a step up one (50 ohms in gives 200 out) and sometimes a 1:1 unit, depending on the band but it's not that critical. I got 2.5-3KW ones so they won't get hot with mismatches and it works great. I got them from DX Engineering. It looks like this one but is a current balun:
https://www.dxengineering.com/parts/dxe-un-43