Performance mode is totally for live and for me dead easy to both set up and use.
I use it exactly as you suggest, 1 slot for clean, etc - just like a multi channel amp. You can then add whatever effects as either on or to switch in and out as a stomp - so yes as you describe OR you can also switch multiple effects on as a combination stomp...lots of possibilities.
Also, Morph is very useful as it adds another element. For example for my main rhythm I have a bit of additional volume and gain for riffs (which is a touch lower in volume than my solo sound but just gives a bit of a push).
Dead easy to set up - choose a performance, name it ( in case you want more - I have different performances for different bands), find a clean sound you want, copy to whichever slot in the performance and save. From that point ( as mentioned above) that profile is now saved as a separate version and so you can name it, tweak it, add effects ( and then resave) without affecting the original profile...and done! Now repeat for all other slots you want.
Its really straight forward, the biggest issue is deciding on what profiles you want and sounds in which slots :).
At the end, you can then balance the volumes to how you like it and then switch seamlessly from Clean ( which might be slot 1) to Solo hi gain ( which might be slot 5). If you name the slots to match this as well its second nature.
Let us know if you get stuck!