[G.R.]

FWIW my wipers only traverse just a few(10-15 deg) past 90 degrees--my Spf was the same -- don't think the Lucas wipers do like a "full" 180 +/- sweep like on most new cars or cars we're used to driving.
One other thing is the position of the arm/blade in correlation with the motor sweep angle--if they are off by several degress from "park" it will make a difference on the sweep angle and the amount of windshield being swept---Trial and Error and I finally got mine to sweep in a position that worked and still park the blade low on the windshield.
RE: park left or right--it may be the wheelboxes are upside down--but I would bet that the wiper motor polarity might be reversed if they park left---spent a day with the dash out trying the wheelbox scenario only to find they were on right, then for out of frustration and for grins I swapped power leads, magically they parked right---Duh--do the simple first--electric motors usually will run in either direction depending upon power and ground connection