Another approach is to set up a pad to drop level by the desired amount, and remove the pad to 'boost'. This gets around the worry of clipping....Where you put this has an effect potentially on the tone. before the amp is different than someplace after the amp. Lots of answers to this question, others can chime in.
So - You just want everything in preset to get louder, like 3db or something, say for a lead?
You can do that in Output 1 block by going to the scene mixer, and you would not need a CS2 boost at all, as one example.
I did not use CS1 assigned on purpose - you could use that. But understand, the more CS switches you have put on a mp block, the more the more it loads it and it can cause crackling - you might have to remove some other CS blocks you don't use (lo cut, saturation, brite switch reverse) to keep the load steady.
If you are trying to goose an amp (more drive) and input, the Filter Block does this. No need to use CS block, use Filter block and set the DB boost you want, then turn it on/off..
@Burgs has a trick that is smart and saves your CPU, he uses the Input Block and makes a second channel (B or C) and then raises the level there. SMART!
Inside Amp Block, with CS:
Assuming you don't want to change the tone, just make it louder. Then you could assign a CS switch to the LEVEL. You'd define the initial level, as the min, and the +3db or so as the max level. When you stomp it, amp block gets louder. Be careful though if using Live Gold, because some presets are hot and adding 3db here may get you close to clipping territory.
After Amp Block, with CS:
Anything goes here - million ways to skin this cat. For example, any LEVEL control in a effects block after an amp/cab will work the same way it does in the prior example.
Take Reverb Block if last block. That LEVEL defaults to 0 (zero).
Open reverb block, then go to LEVEL and left click to open modifier window.
For minimum, put 0, then max value, put 3(db) or your choice -- just don't clip the unit!
Pick CS1 to assign to it. Close/save. Now hitting CS1 will activate the 3db boost in this block.
You could also, CPU permitting, add a Volume block right after the Cab block, before the wet effects, or last in the chain, and assign an Exernal pedal to it (or the CS trick) - just assign either pedal or CS to LEVEL. Now when your pedal is back, it's normal, when you push it down, you get extra 3db.
Experiment. Lotsa of ways to do this. Personally? I would prefer a dedicated Lead scene in the preset, using a LiveGold default lead tone, but then adding the extra volume of 3db or so added in the Output 1 Scene mixer - to punch out. Should be enough headroom so it does not clip.
I set up a VolPan block at -4.5dB before the delay/reverb, as my normal volume, and I bump it up to 0dB for leads. It also gives me a volume pedal in every preset.