Just for the sake of argument, what would be wrong with equal parts of all 4 ingredients? I ask this as a fairely recent convert to "Mix-Your-Own Oganics" becuase this mix sounds somewhat like mine:
4-Way Mix
1 part (store bought) Topsoil.
1 part Compost.
1 part Perlite (or Vermiculite).
1 part "Steer Manure"*.
For each gallon of 4-Way Mix, add about 1 or 2 Tblspns. of Dolomite lime.
* The "1 part "Steer Manure" can be made up of any kind of "balanced" organic ingredients and/or "fertilizers", mixed with the other 3 ingredients (Topsoil, Compost and Perlite) to act as a "filler" so that the volume equals 25% of the overall mix. Whatever you use to make this 1 part "Steer Manure", the idea is to make sure that the potency is no "hotter" than "Plain old Composted Steer Manure".
I've been suggesting this mix to others because the ingredients are easy to find almost anywhere. But I'd like to know if it's really a good recipe - it seems to work OK.
I'd apprecieate some feedback from some "Organic Gurus". Like I said I'm a recent convert to mix-your-own because I got tired of spending the Big Bucks for Fox Farm (etc.).