Having not lived in wales for 8 or 9 years and not ridden off road properly in wales for about 27 years I think I need reminding how steep welsh hills are!
are the rockiest of ascents rideable on a fat bike with low pressure in tyres and a suitable gearing or am I wasting my time sorting my gearing for steepest bits and just push bike to conserve energy? currently running a 11-36 cassette and 34t chainring on 1x10 setup and was contemplating shoving a 30t up front for hills but doubt that would help that much? I doubt it. any thoughts and refreshers for my memory as to the steepness of the hills.

With a trad 3x9 gearing of 22x36 when I was younger and stronger there was stuff I'd not ride up.

I thought fat bikes could go anywhere

Depends where you're going, but generally its not the gradient its more the duration.

My Stooge has a 32t combined with a 42t cassette. There's not much it won't get up but on the technical climbs a lot of that's technique and practice ... but obviously, you're hindering yourself with a fat bike, so.

'plans to take bags off SS later tonight and be realistic/sensible'

I've looked at the maps and it's quite orange in places due the contour lines, I'm going to treat them like Mrs D and go at an oblique angle hoping to catch them out