Broseph400

Going to mount a hydro for the SC. I have a female T fitting since I'm going the dual rear caliper setup. Measured the threads for the female T fitting, its 27mm (got the T fitting from a celica at a junkyard). The male fitting at the hydro is a 3/8-24. What size stainless steel brake lines, brake fittings, and unions will I need? Will be also switching to stoptech lines all around (going from caliper to stock fitting), what sizes will I need to connect to the stock brake line fittings? First time doing brake lines (I am a noob). Another question I have, what brake flare tool do y'all recommend. Any information will help.

Thanks in advance