[PD] JACK MIDI ports in pd / extra port efficiency

[Jon B]

1. I would like to input and output MIDI from JACK (from MusE,
specifically, to use MusE as my sequencer and pd as my softsynth/noise
machine)

I tried just starting pd with things like "pd -mididev 1,2" (-jack and
all of that is in my .pdrc) and it gives the error:

couldn't open MIDI input device 0
couldn't open MIDI input device 1
couldn't open MIDI output device 0
couldn't open MIDI output device 1
opened 0 MIDI input device(s) and 0 MIDI output device(s).

pd starts, but nothing shows up in my qjackctl MIDI connections window.

2. Does it slow the processing down at all to open pd with more audio
ports and MIDI ports than I am necessarily going to use?  (Is it smart
to put 6 audio ports in my .pdrc if I'm only going to use 2 most of
the time?)