My idea is best. No ego involved here, LOL! I built a sort of holster for my one-quart hand sprayer and attached it to my spreader. My version fitted inside the hopper without interfering with normal filling with fert. But you can hang a "cupholder" for your hand sprayer anywhere on your spreader.
Scotts, now sold by Andersons, (and probably made by Prizelawn) makes the best spreader. However, Earthway makes a good one and their 50 pound stainless model weighs 16 pounds less than Scotts and Lesco. Its easier to push and easier to lift onto your truck.