One trick I've seen and used on mine is to get a pair of those arrow
shaped welding magnets whose point is 90 degrees, and stick them
between the fence and the tables. Harbor Freight has them for $1/ea
every now and again.

They'll hold the fence securely in place while tightening; no
guesswork and it works every time (ok, both of the two times I've done
it since the fence typically stays put.)

The same magnets can be used to adjust the height of the blades by
resting them on the edge of the outfeed table, sticking out over the
edge over the blade. Loosening the hold-down bolts allows the blade
to move and stick to the edge of the magnet (one magnet for each end
of the blade is needed). It's now level with the outfeed table, and
can be tightened at your leisure.

On a related question, the knives that come with this jointer are
plain carbon steel and dull quickly. They scary sharpen pretty sharp,
but harder blades would be more convenient. Does anybody have
recommendations for high speed steel knives for this machine?

....John