needle sizes

[TddWil@aol.com]

What gauge and length needles are appropriate for diff types of injection? (IV, IM, and sub cut.)  I have been using 20 x 1". Also, My bottle of epinephrine (unused and hope it stays that way) says inject subcutaneously - how do you do this on a horse - what area? These are grown arabs (no foals) and the substances injected would include Bute, Banamine and vaccines. Also, what is the safest "chemical restraint" to keep on hand in case of (God forbid) a trailer wreck or an otherwise injured panicked horse. 
                            Shelly in DE