Phillip - Potash is a term commonly used for Potassium.  Check the product label to identify how much Potassium is actually in the product.  Then you can come back to the MSU soil test site and enter that number in the Fertilizer Calculator (found under Tools).  The site will calculate how much of that product to apply in one year for 1,000 square feet.  If your area is less or more than 1,000 sq. ft., you will need to pro-date the amount.

Hope that helps.

An internet search for a product with the recommended fertilizer ratios (e.g. 12-0-12 0r 6-4-6) does not reveal any products with these ratios.  Any suggestions? 

Phillip - the ratio of 1:0:1 is a guide for you to use with your fertilizer purchases.  Most garden centers do carry a 12-0-12 product.  If not you can use a 12-10-12 fertilizer that includes the phosphorous as well.  Hope that helps.