And here is the data to create that curve...now GC starts to become thicker then M1 10W-30 only after temperature of 20C which I would not consider a cold start!
TEMP M1 0W-40 GC 0W-30 M1 10W-30
-20 2661.5 2609.0 3424.8
-10 1197.8 1127.1 1332.9
0 599.3 546.6 595.7
10 327.6 291.8 298.3
20 192.9 168.8 164.1
30 121.0 104.4 97.6
40 80.0 68.4 62.0
50 55.4 47.0 41.6
60 39.8 33.7 29.2
70 29.7 25.0 21.4
80 22.7 19.1 16.1
90 17.8 15.0 12.5
100 14.3 12.0 10.0
110 11.7 9.8 8.1
120 9.8 8.2 6.7
130 8.2 6.9 5.7
140 7.0 5.9 4.9
150 6.1 5.1 4.2
TEMP M1 0W-40 GC 0W-30 M1 10W-30
-20 2661.5 2609.0 3424.8
-10 1197.8 1127.1 1332.9
0 599.3 546.6 595.7
10 327.6 291.8 298.3
20 192.9 168.8 164.1
30 121.0 104.4 97.6
40 80.0 68.4 62.0
50 55.4 47.0 41.6
60 39.8 33.7 29.2
70 29.7 25.0 21.4
80 22.7 19.1 16.1
90 17.8 15.0 12.5
100 14.3 12.0 10.0
110 11.7 9.8 8.1
120 9.8 8.2 6.7
130 8.2 6.9 5.7
140 7.0 5.9 4.9
150 6.1 5.1 4.2