Mmm, Motorola Talkabouts are nice to use. I've got some GMRS ones for use in Florida.
If you're going to be driving and using the radio it's good to get one which isn't too cheap & nasty. I've got a couple of PMR446es which aren't too good to use while driving.
Personally I like one which can clip on the seatbelt so it's quite close to my ear and still easy to grab.
I was recently the lead in a convoy of 4. 3 of us had radios. It would have been nice to say "ok, I want to be going a bit faster here so if it's ok with everyone else let's get over to lane 3 when we can".
I was following someone in London once, and they didn't seem to realise that if they went through a traffic light as it was amber I would have to go through on red if I wanted to continue following them.
Same goes for pulling out on junctions and roundabouts; you have to find a gap big enough not only for you but for everyone else too!
Expect and plan for having someone else pull in between people in your convoy. It's going to happen no matter what.
If someone ahead of you pulls in to let a stray vehicle past them, it might not be a good idea to 'flash them out'. I was almost in an accident this way. It happened something like this...
Three cars involved, Car 1 and Car 2 in convoy, Car 3 just happened to be there.
Car 1 went past a roundabout. Car 2 had to give way to Car 3 coming from the other direction, who got between Car 1 and 2. Car 1 pulled over in to a layby so that Car 3 could pass. Car 2 slowed down and flashed to let Car 1 know it was them. Car 3 thought this flashing was aimed at them and pulled into the layby in front of/next to Car 1, who was about to pull out and almost hit Car 3.
Obviously the driver of Car 3 was a little bit tense.