Blakes B83

Bring new to tree climbing Ive bought minimal miscellaneous kit including an 11mm arborist rope (no known make but from a reputable Australian dealer), but it just doesnt make a Blake's hitch grip. Ive read and tried all the different ways to make it work and the only way Ive found works is with 8 coils and the tail going under the first three.It still slides ok when I want it to.
Is there anything wrong with this?
Has anyone else had to do it?