i use rocks myself to cover, pebbles actually, they do help with the perlite floating
a 6-9-6 ratio sounds OK, the numbers should be something like 0.006-0.009-0.006, or something like that, same idea, just that soil is much less hot than straight fertlizer which would have nute numbers like 6-9-6
composted cow manure is typically a good ingredient for mj soil, peat moss is good
too much peat moss may not be so good, soil gets a little too acidic
i use MG Organic garden soil, that's a mix of poultry compost and wood product compost, it works well but the wood product compost is quite acidic, some dolomite mixed in helps reduce acidity, and adds other good minerals
MG Organic garden doesn't have the time release crap, MG has many soils, it can make for a very confusing situation