I understand that, but you're working on an American car, so I figured some Imperial tools must make their way into your hands. Here in the US, we exclusively use the fractions, but I still have a drawer or two of metric tools. Anyhow, looks like you got two solutions for what you're trying to accomplish. I do like the through-frame fittings and if done properly, only require a single adapter to make work. Good luck on the project!
People building American projects outside of the USA have many problems beyond the obvious freight costs ( often more than the price of parts) and delay in getting them . Down this end of the planet NPT fittings are hard to find. Nut and bolt suppliers have never heard of 10/32 threads; and lots more. And then there are also those to whom English is not their first language. Try a foreign language web site and see how YOU manage. 90% of the world works exclusively with the metric measure. We succeed because we are dedicated to what we do, one problem at a time Worked in a spe******t brake shop where we could make up hoses with NPT ends, always seemed a poor subs***ute for proper OE style brake fittings in my opinion.
go onto the rock auto website type in brake tube nut Brake & Wheel Hub > Brake Line > Brake Line Nut | RockAuto even at .70 euro each, by the time you have filled your bottes, when you come to the check out and tax and freight, you will soon be emptying your charette. note the m11 by 1.5 tpi bubble flare for 3/16 line fitting is the one for a 1996 camaro gm 1'' master 1997 CHEVROLET CAMARO 3.8L V6 Master Cylinder | RockAuto that fits the dual can 7'' common or garden gm aftermarket boosters, that allow you to when fitting to a 35-40, place the master and booster so as to have the cap just come up through the floor enough to screw on the power bleeder and not drop you cigarette ash and other detritis into the resovoiur. ideal IF you also need to utilise a non opaque bottle and also need to fit a float to have a low level audible alert - dependant on where in the world you are, don't (blue bear) burn it in good (blue bear) as you will need to tweak it to perfect when the thing setllles, thats the thing about them iron c3 jobbies, you can see just how wonky the fluid level is, I suppose its one of them you cant see it so you dont have to worry