Y60 Window regulator replacement

Hi All,

Had to replace the nearside (power) window regulator on my Maverick.

Job wasn't too hard , even for a newbie like myself. $30 next day delivery...sweet !

But...

The window tilts forward when going up, meaning it wont sit in the rubber channel ( leaves a gap in the top rear corner) unless guided in by hand.

The manual says that I need to loosen a couple of screws, fit the glass into the correct position ( top rear corner in tight) so that the glass runs inside the groove and then retighten.
When the glass is fully up & in position , I can't access the screws to tighten them.

An old review of the Y60 says that the window regulators are a weak point, so I'm sure a few of you have replaced them.

What am I doing wrong ? How can I get the rear of the glass to stay in the groove ?