The road camber problem is less noticeable with a good quality skinny tyre.
“Road camber problems” are the sort of problems you get when you ride across a slope, rather than up or down it. Many roads have a “camber” which means the centre of the road is slightly higher than the edges. This is for drainage. other roads are deliberately cambered in the direction of a corner, like a banked race track, to help motor vehicles travelling at normal traffic speeds.
If you are riding across a slope (e.g. along a cambered road) and you are trying to keep your unicycle vertical, then the width of the contact patch is critical.
The theoretically perfect wheel would have no width at all, but this could never exist in reality. A skinny tyre might have a contact patch 10 mm wide, and a fat tyre might have one 20mm wide. (These are not accurate figures, but simply to illustrate a point.) The width of the contact patch will depend on the shape of the tyre, the pressure in the tyre, and the steepness of the camber.
Along the central axis of the tyre, the rolling circumference is at its greatest. the further you move to one side, the smaller the rolling circumference.
Thus, when you are riding across a camber, one edge of your contact patch (down slope) is where the wheel is largest, and the other side (up slope) is where the wheel is smallest.
So, instead of riding on a nice round tyre, you are effectively riding on a truncated cone. You can all visualise what would happen if you rolled a cone: it would turn one way. So, the tyre that is being ridden across a slope will tend to turn up the slope. This effect is sometimes called “coning”.
It follows that, all other things being equal, the narrower tyre will have less coning effect than the wider one.
A secondary effect is that a narrow tyre will tend to be shallower (lower profile) so you need a higher air pressure to be sure of keeping the rim from “dinging” if you hit a pebble, kerb, etc. The higher pressure will contribute further to keeping the contact patch narrow and reducing the coning effect.
Some of the same factors contribute to making a (good) skinny tyre much easier to steer. The ideal tyre for steering has a rounded cross section.
However, the sensitivity to bumps and sudden changes in the rolling resistance of the surface on which you are riding is more noticeable on a skinny high pressure tyre. This is partly due to the higher momentum of the fatter tyre (it can ignore minor variations) and partly due to the reduced air pressure in the fatter tyre, which can soak up the small bumps.
So, riding a skinny high pressure tyre is great fun, and feels precise and controllable when steering, but it can be hard work over a long ride on uneven ground because it requires much more concentration and adjustment of speed and pedal-force.
On my 700c X 28mm tyre, with 102 mm cranks, I have done some light cross country. With 110s, it is surprisingly nimble. The tyre becomes a limiting factor only when traction is poor, or when the ground is yielding, or when the ground has sudden changes in contour (e.g. tree roots etc.).
I haven’t ridden much recently, mainly due to old age, bad weather and other commitments. However, writing about it is making me miss the 700c - it is the purest form of unicycling that I have tried, because the tyre has no built in margin for error on uneven ground.
Also, it is good for drops of up to about 5 feet.
Too keep the interest of the reader, I have included one factual statement in this post that is not actually strictly true.