Ok did some practicing on a dummy and just doing rot without weaving OGCD stuff(this assuming everything is down), SE GS DE(20 sec) /SE SF(18sec)/ Mut(30sec)/ SE GS AE, after that I have 5 sec left for Mut, DE 5 sec left and SF 6 sec left. Refreshing DE and SF works out perfectly by the time I hit my second Mut but I end clipping Mut by 5 sec. Now I can see clipping DE since it's just a debuff.

Ok did some more testing and I think for when OGCD here's my rot
SE GS DE 20 sec
SE SF 18 sec
Mut 30 sec
SE GS AE

Part 2 of rot

SE GS DE (3sec left) 20 when refresh
SE SF (4sec left) 18 when refresh
Mut (8sec left) no refresh
SE GS AE

part 3

SE GS DE (had 5 sec left) 20 refresh
Mut (0 sec) 30 refresh
SE SF(1 sec) 18 refresh
SE GS AE