I have done all three heads triceps are a leaner muscle so I use a 29 g 1/2 inch insulin pin. Typically if you raise your head above your head it stretches your skin tight and you won't even feel it go in. Hope this helps.
ok an update:
its been 3 days and the site is alright. it was slightly red and swollen on my left side only but def tolerable. plus it made my elbow pain much better. think i'll keep at it, not more than 1/3cc at a time.