You can get glyphosate at a farmer's feed store for about 1/6 or 1/8 the price of Roundup. Got 2.5 gallons for a little over $40. This could have cost over $300 at a garden or home store as Roundup concentrate.

41% ? You mean at least 41% glysophate in the concentrate right? To mix with water, I typically use 8 ounces of the concentrate per gallon of solution ready to spray.