Good write up. I could have used that myself yesterday when I changed my own H4 lamps. I also changed them to Osram Nightbreaker Plus lamps. I have been using these is all my motors for some time now. Much brighter beam than original equipment. Anyone doing similar, make sure you get the ones that say "Extra Lifetime" the same as the ones that Richard fitted, as lifetime is definitely shorter with these performance lamps.
I would add that it is best to you have everything to hand or have a work platform level with the headlamp to support the headlamp otherwise the headlamp would be supported by the sidelight cables and the headlamp touching the bodywork. Not a good idea.
Another tip. Assuming the old beams were correctly aligned, on a flat wall/ garage door mark the position of the beam pattern (I use masking tape) so when the new bulbs are installed compare against the marker and adjust accordingly.
I just need to get out for an evening trip to see the improvement for myself and to decide whether or not I need to fit driving lamps.
