One problem with FH is the tendency for the ball to bounce when it travels across the metal flap, and hit the wire form gate above, deflecting the ball back out. Traditional wisdom is to slide a bit of card in there. I did this originally, but found it came loose. A bit of glue might have helped. When doing a swap for a new IPB repro playfield, I decided to add a new Pinball inc. ramp (thanks Greg!) and this is thicker, better plastic but seemed to guarantee that the bounce would be worse. Its caused by the ball bending the flap as it travels over it, and being spring steel, the ball gets shot upwards into the wire form.
So - my anti-jump main ramp entry solution (which actually and surprisingly being my idea seems to work really well!).
Take one skinny "animal shape maker" balloon. Use an orange one and it looks perfect.
Cut it to an inch or so longer than the width of the entry.
Add some form of funnel to the cut off balloon.
Mix some epoxy, and pour in maybe 3 mils??? Just enough to leave you able to tie the end and it is not "full', ie lots of give space available.
Put it in the gap, screw down the front entry flap and position as if complete (all other screws etc).
The pressure of fixing it in place forced the epoxy filled balloon into the exact shape needed to remove the flex inherent in the design that causes the jump.
Leave a few hours to really set.
Snip off the tied up end.
Install Cliffy protectors (mandatory step!!!!!!!)
Never have a bounce again, and the shape of the formed piece means it never moves, so is a permanent fix but just loose due to the balloon so everything can be removed in future for maintenance.