Advice for aircraft HF radio please

I occasionally ferry light aircraft from the USA to Europe and beyond, and many times, HF radio is mandatory (e.g. when crossing the Atlantic, direct), in which case I rent a radio (and tuner, and 24/12 converter). However, I would like to buy a used radio, if I could find one with the right spec. Comments as follows -
1. Are there any models I should particularly look for? It would be ideal if I did not need a separate tuner, and even better if it was 24/12V capable, to avoid the need for...

Advice for aircraft HF radio please