dailydriver I like the Sustina 0W-20/RL 0W-40 blend.
A nice upgrade to the M1 0W-40 blend if you don't mind the higher cost. Your 2/4 ratio should net a HTHSV 3.5cP, 205 VI 0w30 oil. Reversing the ratio would net a 3.0cP, 215 VI 0W-30.
For those that don't like to mix brands a Sustina 0W-20/0w50 blend will acheive similar results at least in terms of VI.
Another oil to possibly include with any M1 0W-40 blend is the some M1 R 0w50 (HTHSV 4.1cP, VI 189, Moly 1,650 ppm, Phos 2,500 ppm) if you want to boost the Moly and Phos level of the blend for track use. I wouldn't use any more than 25/30%.