A number of years ago a friend on mine fished one fly in various colours and sizes for a whole season. A hackle less EHC. He used it in hatches of upwing flies, caddis, midges, the lot. He noticed no difference in the numbers of fish caught. Now he considers a dubbed body and deer hair wing a better all round fly than the EHC. He even uses it in size 8 and 10 for sea trout (sea run browns) for his daytime fishing.
Cheers,
A.