So will make this a quick one. I follow Tim (G5TM) on Youtube and he published this video on coax.
Long and the short of it is basically is treat your antenna as a ‘unit’, i.e. the antenna itself (wire/beam/loop), the connectors and the coax, and in your budget the antenna system is as crucial as the transceiver.
I also asked my long-term mentor and friend PA2TG his advice – guess what the recommendations of both G5TM and PA2`TG recommending the same coax to me for my needs (HF)!
100m 
connectors and scissors
With that I have ordered and now received some UltraFlex 10 and connectors from W&S, plus the scissors to help me make a good job of it. There is this excellent video on how to put the connectors on the coax.
Having received an email from M0MCX that the “Nebula” will be here any time soon I am naturally very excited to see how it all operates !