when i fitted mine, i used spade connectors to go onto the bulb terminals with rubber insulation round the connectors.
Just a case of working out which wire is the dipped beam and which is full beam, then wiring them to the relevant bulb. I didnt re-use the existing ground wires, instead I made my own and used existing bolt holes as grounding points.
Indicators and sidelights are the standard connectors, so no rewiring to be done there.
Its effectively just 4 wires per unit, two which are grounds. Trial and error will see you right in the case of working out which is dipped and main.
As for the wire itself, I bought 15amp (i think, cant really remember) wire on a reel from Halfords, but to be honest thats even heavier than what you'll actually need.
