all blocks already have stereo outputs. there's only one "line" connecting blocks, but it's Left and Right. if it's a mono output, of course it's just the same signal going to Left and Right. some blocks though are mono INPUT. i know Amp and Mono Cab blocks are, and i think Drive is, one or two more at least. those will sum the incoming stereo signal to mono, but provide a stereo output in case you pan something.
so for the 4cm discussion, without an Amp or Cab block in the preset, you're pretty much set for mono or stereo operation without changing anything further.