Hi Ken,
I’m doing pretty much exactly this but in reverse: starting with the Invierno from Ponferrada to Santiago - Bus to Leon (ALSA bus at 3pm, takes just under 6 hours) - Salvador to Oviedo, Oviedo to Santiago via the Primitivo - onwards to Finisterre and Muxia.
Initially, I wanted to combine the routes like you suggest in your post. But:
- the Camino de Invierno seems physically less strenuous so a better „warm-up“ option
- climate wise it seems to make more sense. Less heat on the Invierno and less rain (chance of snow??) in the mountains later on
These things might not be important to you if you are in training. We‘ve just finished our post-grad degrees and spent the last months stuck in front of computer screens. Starting with the Invierno gives our legs a comparatively easier start. Weather is a play of chance anyway.
If you do stick to your schedule we might bump into each other on the Salvador - our tentative plan ist to start in Leon on the 23rd with 8 days to Escamplero.