1) Syringe out a line of sensitizer at both top *and bottom* of the coating
area; even if the line of sensitizer 'beads up' on the first pass down the
paper, you can still pick up the full line at the bottom of the paper,
which usually suffices to fill the gaps.
2) With 'hard-sized' papers, the angle of contact between the surface and
the sensitizer liquid can be decreased by adding a wetting agent - but, be
warned, this can also introduce other problems! I recommend a non-ionic
surfactant such as Tween 20 at a final concentration of 0.2 to 0.8%
depending on sensitizer and paper.