I just posted this on the Dolomite lime thread.
7.5 gallons is 1 cubic foot
3 half filled 5 gallon buckets is 1 cubic foot of soil, this is how I measure for mixing.
Hope that helps
Edit: my mix would look like this.
1/2 bucket SPM (peat)
1/2 bucket aeration (perlite)
1/2 bucket compost or EWC
1 cup lime
about 2 cups of amendments such as kelp or something like garden tone
I add 1/2 cup Gypsum also. I have a specific blend but this is a simplified version.