it depends on your market. on my market titan sd is the standard sd transmitter so i invested on these-also they are bullet proof-. by using a transmitter generally used in your area you can just give the receiver to the video assist and then he/she could set it up while you're seting-up the rig.
if you invest in titan SDs, know that there are 2 versions availeble:
US version, metal housing and 4 channels.
EU version , metal housing covered in plastic in order to prevent interference and 10/4 channels.
also high performance 9Db titan antenna does wonders about the already impressive range.