Yes I like that blend although I might even go a bit lighter with a HTHSV of 2.8cP or there abouts. What you could do, is only fill to the low level on the dip with the 4 qts Sustina and 1 qt RL then do an oil pressure test for 200 miles or so noting you lowest OP at the highest oil temp' at high rev's. Then you can add either more RL to raise the OP further or more Sustina to lower it if it's still higher than your target which should be 52-53 psi IMO.
We have another member with a Z0-6 Corvette that's running a TGMO/M1 SM 0W-40 85/15 mix with a resultant HTHSV of 2.7cP and he can maintain oil pressure in the low 50s psi at normal summertime street operating oil temp's.