I can't answer name brand enquiries, but we have had generic Krylon here for many years.
So I'll provide MY sincere and useful experience.
For more than 40 years I've been painting British made (imported) lead alloy figures.
-Yes, if you do not apply an undercoat of some kind, even enamels will chip off.
-Yes, a 'metal' enamel style paint, and thinner, we call it Mineral Turpentine (a petroleum oil distillate) applied as a wash over whole figures works well.
The target is to cover all metal, any bits left no matter how deep are potential 'crack' points later in life.
The reason for using a light flowing wash is to make a very thin layer of adhered paint. Not thin enough to brush off with a finger (since these require at least some handling) but not a full deep 'coat' of paint.
The aim is to produce a seal that stops all air contact with any metal surface (bases excluded and I've never seen a base go defective). This means the wash produces an effect that lowers surface tension; water based paints then adhere BETTER to this surface than they will plastic or bare metal.
I use black purposefully. (Humbrol Matt Black #33 and in times of shortages Tamiya Enamel Matt Black) equally good.
These are both effective on metal AND the modern plastics (Perry).
I have used white, both matt and gloss, at different times. However, coverage by other colours was affected and in the end, all those in white got stripped again, even after years.
Spray cans? Well some can provide a soft mist that spreads but I feel the mass of paint is sadly not on target, gets too clumped and you just cant fill the detail (or base shading when/where you want it).
A large amount of my painting now is dry-brushing layers across a few figures; not gawps of paint on 50-60 models like the old days. More subtle, less mistakes and finer control, if you're not in a hurry.
Trust this helps,
regards
≠davew New Zealand≠