After fighting with Racerparts Wholesaler for week on how to arrange payment for some SS hoses and AN couplings I decided to cancel the order.
Instead I used hydraulic lines from the local TESS hydraulic shop.
These are industry standard parts with at least the same quality as Aeroquip and other brands selling AN type fittings and stuff but they are heavier and not made of aluminium. I don't care. The whole assembly weigh less than 4 kilos.
The hoses are steel braided with an additional rubber layer on the outside.
Here are all the parts including the sandwichplate.

After some fiddling I ended up with routing the hoses like this:

I'll go down to TESS tomorrow for attatching the couplings to the other ends now that I know the exact length.I read on miata.net that some guys had to remove the support for the intake manifold to make the Mocal sandwichplate fit. I did not have any problems with that.
It's a tight fit but enough room to change the filter without any problems:

The next step is to cut a slot in the bumper to get some airflow to the oilcooler. We'll se how that turns out.