My oldie has to be sedated for teeth and he has to have them done every six months, but he is 17hh and a real monster to 'do things to' so we tend to do all the other jobs (sheath cleaning, jabs, blood test for tapeworm etc) while he is compliant!! He seems to find the whole experience much less upsetting when sedated a little, I held out against it for years but am comfortable with it now, tho I wouldnt want to have someone elses horse sedated in my care.
Havent too much idea on tails tho...:-))