I do indeed work for Novation (and as a result, Focusrite, ADAM Audio etc).
The patches should all be a similar volume, although of course if a patch is more focussed on low end, it's perceived volume through say some cheap speakers or headphones might be less than a patch that is more lead-line focussed (higher pitched content etc).
From memory the main volume control is in the analogue path and so can't be saved per patch, as such I think probably the best way would be to use the mixer section and set the oscillator level (balancing as needed across 1, 2 and sub) per patch, and then save that patch. There's not a way of 'matching across all patches', but if you're just talking about going between a few patches for your live set or whatever, this is quickly achievable.
For anything more depth, give Technical Support a quick call (PM me for the number if you need it), and they can go into a bit more detail
Cheers
Si