5-10-10 is ok, but there is not much to it, and you are still fertilzing the grass and weeds. To put down 100 lbs/acre of Potassium you would need to spread 1000 lbs of 5-10-10. Potassium and Phosphorus do not leach into the soil very well like Nitrogen does. With enough rain/moisture the clovers surface roots will utilize the Potassium at the surface though.

At a local mill near me they sell a 8-20-28 for about $12 for a 50 lb bag. 0-0-60 Potassium for $14 a 50 lb bag. Look around in your area for similar products, you could get more of what you need on your plot for less work/effort.