My thoughts:
- how many days/km's of skipping are you thinking about?
- at least don't skip the first week of your camino from where you are now. There are still nice parts coming. Two years ago, I also started in Le Puy and due to circumstances I had to skip about 8 days. After some research we skipped Montcuq till Mourenx because it seemed to be a less exiting part, and from Mourenx it is nice to walking towards the mountains. Because I don't know what I missed, only people who did the whole stretch knows if I was right. Public transport was quite difficult so we did some hitchhiking, which worked out fine for me and my wife.
- Like said before, transport in Spain along the camino seems to be much easier then in France.
- To start on the frances (in Spain) while coming from another route was difficult for me and seems to be quit difficult cultural shock for everyone. From that pov, I would prefer to skip some spanish part
- If money is an issue: Spain is much cheaper than France. Better then to skip a french part.
- I don't know how you feel right now, but it might be that your body really gets used to walking, which can make your average a day going up. Because of that, only near the end you will know more about how much to skip and can now feel free to walk whatever you feel like.
- Personally I would prefer to skip a bigger part only once instead of skipping more times a smaller part. Skipping interferes my flow a lot and it also makes me loosing the people I got to know around me.
I second Pano's words: whatever you decide at the end will be good for you. Ultreya!