Is there any easy way to see what buttons you have available & which ones have been assigned to a set task?
Not that I'm aware of, because each wheel has different buttons, knobs, rotators. The way I first did this was print out a picture of my wheel and use a heavy black marker to label each command on the picture.
In VR, it would be nice if you could post an image in the MFD that shows which buttons do what. In IL-2 Sturmovik, you can paste a photo on the dashboard and that means you can have a cheat sheet posted where you can see it. Personally, I use VoiceAttack to code my buttons so I load a different profile for each car I drive.
Every wheel & button box is different. Pretty much you need to figure out which functions you need mapped first in terms of priority and then create your own picture. What I did was use a spreadsheet to list the functions, gave them a priority, and then, like @davehenrie, labeled the buttons on a picture. There are a few groupings of buttons by feature, so, for example, every feature around a pit request are usually assigned to a funky switch and that has a fairly high priority. For the occasional endurance race, the driver/spectator swap buttons are grouped together. Note that if you drive more than one sim, you'll want to also figure out what functions are common to all, so the spreadsheet is going to be a bit larger. For instance, AC has a KERS button that is not in rF2. Here's a starting point I made for the Fanatec McLaren wheel and I currently have the funky switch in the lower left handling pit request features (is labeled unassigned in pic):
Add to this, Fanatec sells little stickers you can place on the buttons that match most of the available assigments. Someday I'll get around to using those as well.
