Bro im using same mix of ffof/coco. Curious how your plant final result was. Personally I thought your issue was light related cuz of the leaves curling down but we'll never know so i won't debate seasoned growers. But light burn kills taste since u spoke of harshness. Once I moved my light 24 to 30 inches things got better. Late bloom issues don't worry me cuz u can still have a nice harvest and great buds. So far I personally like the mix of ffof/coco but im only 3 weeks in on this run. Let us know how your grow turned out in the end. There's alot of haters that will never bend on mixing mediums but I believe with experience and knowledge u can make anything work the way u want it to and produce quality bud.