The Insurance Institute just did this on new vehicles and the results were poor: http://www.latimes.com/business/autos/la-fi-hy-car-headlights-20160330-story.html  Video here: https://www.youtube.com/watch?v=3Sp7nvuOxtY 

I think the best way to test is on the road--a long straight one on a dark night with reflective and non-reflective images down the road and measure the distance when they come into view. A stuffed deer would be good. ;-)  You'd have to close the road unfortunately to do it safely unfortunately, or find something on private property.

The 80/100w H4s I have on my '85 look just like the bright lights in the video.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Brent Weide
Sent: Wednesday, April 06, 2016 7:15 PM
To: vanagon@GERRY.VANAGON.COM
Subject: 91 Headlight Upgrade

Folks:
I'm about to embark on the upgrade of the 1991 square 9004 headlights to the early vanagon H4 round headlights and would appreciate  your assistance.
Does anyone know of a way to accurately measure the improved lighting using every day tools?  I'd like to measure that headlight strength before and after the change.
I'll be documenting the change (good or bad) on my website and appreciate your feedback.

All the best,
Brent
--
Brent Weide
Portland, Oregon
www.weidefamily.net/vanagon/