I’ve used a pump and plaster mixer both do the job well, personally I prefer the mixer. There is no need to heat any water with the mixer, the most I ever did was pop a hot feed into garage. Late season the ability to warm already mixed syrup is handy. Bees don’t like cold syrup so if you can warm before putting it on all the better. If set up correctly pumps can mix plus tank up. Check your pond shop for fittings, plumbing shops don’t have the sizes. Pond shops have 50mm hose, gate valves and the like. A 50mm valve/hose takes about 20 seconds to fill a 25l can from a drum. Should add hedium sized sds drills also will mix a drum and available cheap at diy stores although you may need to add an adjustable Chuck. Plaster shops have a multitude of drums and paddles/mixer attachments. Ensure any drill or mixer has variable speed plus a trigger lock. This is a simple frame to hold mixer above a large drum.