I went with the S2 Sports on my ride, all around. So my cargos are S2 Sport which are PLENTY BRIGHT for seeing behind me. If I could do it over again, I'd PROBABLY go with S2 Pros for my chase lights.
S2 Sports would work great in say rain/snow places but after coming back from Rausch recently I wish I had S2 Pros so they'd be really bright through the dust. You could still make out S2 Sports but Pros would have been a LITTLE better.
The goal is NOT to light up the trail behind you with a nice clean pattern with chase lights, it's to let the guy running up on you SEE you so he avoids HITTING you. This is why almost all of the chase lights ran, are amber. As it's the best color choice to cut through bad weather.
If you REALLY wanna do it right, do the GJ Motorsports brake light + a Baja Designs RTL bar which you control. This way if you are running slow you can throw the blinking light on. It's an indication you are going slow so that someone coming up on you KNOWS you are slow.
We don't sell a lot of RTL bars until race season, then they fly off the shelves.