Fitting new halogen kit to Herald 13/60

[A TR7 16V]

I've got a rather nasty brown headlight reflector on the herald as a result of it being stood out in the rain of West Lancs right through the lockdowns. A good test of the hood I fitted though, which ain't leaked at all that I can see.

Anyway, as it just about works, I ain't gonna mess with the headlights till the halogen kit I've ordered turns up. But when it does I wanna fit stainless screws wherever I can. 

So I wondered if anybody's done this job recently and knows what screws are likely to be needed? 

Also any hints and tips like about sealing the surrounds up when I'm putting it back together? 

The kit I've ordered is this: https://www.ebay.co.uk/itm/401982976657?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

Graham