I don't think you can "tailor" your LOR's to the adcoms. Every school look for different things. My profs and dentist just told me that they put examples of my qualities and how I contributed to the lab or office. One of my profs said he liked putting concrete examples so the adcom know that I didn't just find some prof that needed my CV and a draft LOR to help him "remember." Hope this helps.
*Concrete examples as in: Student was responsible for culturing frog embryos which requires constant monitoring and punctuality in husbandry. Probably not what he wrote, but something along those lines, because I had to go in every 2 days at 6:00 am to check the logistics.
