headlight upgrade

[Major Rant]

Cans I use any H4 bulbs, particularly the "up to 90% brighter" bulbs, or are there some to avoid?

In a word ... Yes!

But you take your own risk , you should be aware that most of what's written about them is either "Marketing Speak" or "Paid Placements" from vested interests
(ie its mostly Bollox!). The truth is that they are simply H4s with better material control and a slightly more 'inert' gas filling that allows them to be driven harder.

I used "Osram Nightbreaker" H1s in the car and so far they are fine (2 years old).
They claim "All Osram Night Breaker bulbs are UV Protected and so are suitable for use on vehicles with plastic headlight lenses" .
They also claim that their new ones "Nightbreaker plus" have 50% more lifetime than the originals.

There are Philips equivalents but I would avoid other makes unless you can see evidence that they work as well.