I haven't read that link, but in preparation for any spays I have seen my girls through I have fed them a variety of fresh to find out what they prefer (so that I know what to tempt them with after). I also got a second bowl in with them and experimented with what they liked added to water, again to tempt them (my bunnies vary from a drop of cranberry/apple juice, or water that has had banana/basil/mint soaked in it).
Lastly I syringe trained all my buns so that if they needed meds after I didn't have to handle them, they just knew that the syringe held something good and would come over for it. I did this by using diluted apple juice and poking the syringe through the bars, and the buns would come over and I would allow them to drink from it. They see it as a treat, and it has worked excellently, and when they have not drunk themselves, I have been able to encourage them to drink this way too.