Did you have a look at Geller, they habe quite good prices, even for Bio.
I know Geller quite well. He was almost up and about to move a truckload of bees to me for pine-honey, but cement-honey got in between. But as for feed, nowadays we are required to buy "Bioland", not just "bio".
Thats new, but maybe now no more south american sugar, when it is available produced at home.
For everyone not familar with the term "Cement-Honey" it refers to Melezitose containing honey, which settles dead hard in about 3 days in the combs. If you geht the brown variete, beautifull honey, but hard to harvest, since you need the bees to move it a second time and then use that short time window for harvest. Wie had the same problem this year even up Herr.
For the recipe I just make it up to my feeling, i gues about 20% syrup to 80% powdered sugar.