MK 3 Headlight replacement ?

I need to replace my 7 inch headlight but the only replacement available locally is this one:

7019SS Wagner semi sealed beam 12V H4 base
48881 Halogen bulb (60/55 watt)

This wagner I am told would have an approximate 5 amp draw when on high beam, my question: is the MK3 alternator up to supplying this H4 Halogen ?.. I am also finding it a little hard getting around the idea of this setup having a protruding flat lense as opposed to the the original curved Lucas.. Looking over images of Jerry Does MK3 (Access Norton) I am thinking he has replaced his with one of these but I do know he upgraded all the original electrics ..

Appreciate your thoughts on headlights and what other members have done in the past when replacing on a MK3..

Cheers and have a great Easter
Paul ...

I had a Cibie 55/60w halogen lens and bulb on a stock 850 Mk1, and the electrics handled it OK.
I didn't do any 12 hour trips in the dark, so don't know if it was fully balanced, but couldn't detect any charging problems.
Great headlamp, way more light than the stock one.

Electronic ignition will draw a few amps more, as will heated handgrips and jackets, however.
The leccy starter will soon tell if the battery isn't getting enough charge !

get a hella semi sealed beam unit. I has a flat front, the does not protrude like the wagner you get from repco. They are as good as each other. I have the wagner on my 850 and the hella on my 750. As I have said before, run a heavy duty earth anf power wire direct from the battery and through a fuse, Use 2 relays to get a bright light. As said vbefore, if you like candles, forget the relays and the heavy duty wiring. Over to you. On pres of nocnz said I had the brightest light he had seen. go figure.