Maybe you can look up Australian biodynamic farms? They are often massive by our standards.
Maybe Alex Podolinsky's efforts would help you? He managed thousands of acres biodynamically:
http://www.ifoam.org/growing_organic/definitions/pioneers/alex_podolinsky.php
or:
http://www.demeter.org.au/what.html
Biodynamic farms can be very small.
Obviously, the cheapest way would be to make your own BD500. I do not make my own, but I do not have a ranch. If you already have
cattle and manure, it would be better to do it yourself.
The Pfeiffer Field Spray is basically microbe food - it just feeds the bottom of the food chain. Bacteria have the highest protein by weight of any organism in the soil: provide them food, and they show up... then earthworms, and your soil begins healing itself.
I expect if you simply composted your weeds, manure, etc. and used the finished
compost as a diluted "compost tea" this would suffice. An orthodox biodynamic farmer might disagree with me, but you have to make do with what you have. And a shared principle in biodynamics and
permaculture is: creating fertility from what you already have.
Check out E. Pfeiffer's "Soil Fertility, Restoration & Preservation" (free .pdf here:
http://www.soilandhealth.org/01aglibrary/01aglibwelcome.html)
I know a number of these farmer-thinkers would use extremely dilute homeopathic forms of these preps with apparently good results. Think again in terms of microbe food: you don't need much to jumpstart the process.
The BD500 spray, from what I can tell can benefit from spraying both when the Moon is "descending" (during what Maria Thun calls the "transplant time") AND in the very late afternoon. The logic is: you want it to soak into the soil, not evaporate; the moon, when "descending" is supposedly pulling
water down into the soil.
I hope that helps. This is what I've extracted from much reading.