A sail like a NORTH CODE ZERO or reacher or similar requires substantial amount of luff load to maintain sail shape. This high amount of luff load translates to rig compression and puts additional stress on the rig as compared to a relatively softly loaded spinnaker. The sail materials also make a difference on rig compression. The less stretchy reached and code zero sails also increase rig strain.

As to penalties: There is a far greater range of TWA (True wind angle) capabilities on a reacher compared to a spinnaker. The wider range increases the penalty to compensate for the additional use and MPA (Maximum projected sail area or at least potential) over the full range of the course.

LIFTING THE BOWS...? Sails with an acute angle of rake provide additional lift. Witness AUSSIE 18s where only their rudder is in the water at times downwind.

In my experience a flat spinnaker provides more lift than does a reacher or "hooter".

MM