Guys im redoing my brake lines with nicopp brake lines. I have a tool that does the 45 degree double flare but it don't look like the oem flare. Oem is slightly smaller and sits flush in its nut.
I found this site that says a lot of Japanese cars employ a 37 double flare. Check this site out ... Brake Line Flares: Metric & SAE, Inverted & Bubble - Win HPDE
I bought another turret that does 37 degree double flares to see if it does fit better.
I also bought Dorman Japanese nuts that look like the oem ones.

 

Dorman 490-711

 

45 degree double flare is correct my friend. what tool are you using? i recently did all of my brake lines and tucked them. they are all 45 degree double flare or as some others might call it inverted.

 

I used my Eastwood turret-style flaring tool with the correct inverted flare. I also noticed my flares were not identical, but I chalk that up to the original flares having been seated into the fittings. I haven't finalized everything, but I'm confident it will be fine once everything is tightened-up. The Eastwood flaring tool is awesome.

 

Here is some flaring info, with pictures! From Rob Robinette's old third gen site.

And here is some info on DIN, SAE, and JIS brake flares.

 

45 double flare is definitely what you want. I've always used one of the handheld ones that looks a bit like a lump hammer. Don't worry about how it looks compared to the stock steel lines, as long as you get a good metal to metal seal with no leaks you're fine.