To convert a smaller gauge antecubital IV to a larger bore IV follow the instructions shown in this link:
Inserting the RIC catheter in an antecubital vein is essentially the same as inserting a Cordis Introducer into an IJ.
Replacing an 18 or 20 gauge antecubital IV to a 12 gauge catheter will allow much more rapid infusion of blood and blood product. With a 12 gauge catheter the Belmont Rapid Infuser will deliver 750 ml/min.
You won’t be able to hang blood fast enough for the Belmont to deliver it.