Imagine my surprise that he is not on board with metronomics …  saying that there is plenty of abstract info available but no real data that shows it works..

The same can be said for lots of things about treating cancer, and in the long run, you are the one who gets to decide what you want to do. Some people are more comfortable with lots of hard data, others not so much. You are doing well by looking at all your options, and then figuring out where you want to go.

As for 

He did remind me that this is an often fatal disease where more than 90% have mets in lungs on or after year one..

Of course. But many live longer even after mets are found. It's important to balance reality with hope in this journey, it can be the best medicine for both ofyou.

I can't offer you any advice about when to give the Peroxicam and Sulfacrate, that's a question for the vet. Let us know what he suggests.