I have just done a trial pack of the recommended list from the Confraternity of St James into a 45+10 li Dueter Guide. The pack was more than large enough for that. The CSJ list is a bit tight in a 40li Macpac Adventure Racing pack. Both configurations come in around 10kg.
To satisfy my own curiosity, I also packed what Sojourner47 lists as his load, and I was able to fit that into the 30li Salewa Summit, but with no space left for food! I suspect it needs a 35 li pack to give it the flexibility needed on the Camino.
More importantly, it is just over 8kg in what is a relatively heavy pack at 1.3kg. Sojourner47s list is one of the few that gets below the 10% of body weight when I pack it with my gear, but seems to be best suited for walking in late spring to early autumn, and I think it would need some additions in colder conditions.
I think the pack you have chosen will be more than sufficient, especially if you are travelling early in the year when you might need to add some thicker items such as thermals, warm gloves, a beanie, etc. You will now need to avoid the temptation to put little extras in because you have the room. I did this when I walked the
Camino Frances in 2010, and eventually posted most of the extras home, but they were a great encumbrance until I found an open Correos.
I prefer boots, but also prefer leather to fabric. I walk a lot here in Australia in summer, and I find that fabric boots with a waterproof membrane tend to retain sweat more than a leather boot. If you are walking in warmer conditions, and find this, you might need to change your socks during the day.
Also, with most membrane based waterproofing, you shouldn't wear any cotton underneath the waterproof layer. So you will need to avoid socks with any cotton content. Good hiking socks normally aren't made with cotton, but recently I have seen some with a small amount of cotton, so it will pay to check.
Regards,