I now have 1500 miles after a rebuild (1000 miles on the oil change after the break-in period). Today I checked and the oil level was down to the minimum line, so I had to add about 1.4 pints (.7 litres). Is this normal?

That's not too bad, the rings have to seat. I believe adding 1 liter per oil change (3000 miles) is normal. some engines use less, but it shouldn't use more.

BTW, how do I break in an engine?
I drive it like I stole it.

Mark is right. Drive it like you stole it, but do run it a constant speeds. Hammer it from time to time. Rings probably have not set up yet.

1500mi and rings not seated? That seems long to me, no? I am not an expert.

I agree, modern rings generally seat within 500 mi or so. I'd guess oil scraper expanses overlapping on at least one probabl more cylinders. If it doesn't sort within 3k miles, it's time to tear it back down and find the problem.

My questions would be:

Were the cylinders honed properly?

Were the pistons and the bores measured for trueness and matched?

Those are two biggies that will screw you every time. I have learned this before a long time ago

Depends on the brand of rings. Seating time varies widely from brand to brand.