Hi Mike-uk,
first of all thanks for the kind words.
Quality wise, you can start by leaving the default options and judge with your eyes the result. If HCenc VBR 2pass is not auto selected, you can force it in Edit Title > Video > Video Encoder. Then you can play with HCenc Advanced Options.
There are no magic rules to obtain the best result: the "best" depends on the type of video input and your subjective evaluation of the output.
I agree that PAL Speedup is the optimal choice for NTSC-film to PAL conversions.
There is also the possibility to use the ff_vbr plugin by manolito, which brings FFmpeg to its max quality level. I would leave manolito to jump in and to explain how it works.
Bye