Those are all just matters of preference. Any combination would work. The only critical variable is adjusting distance above substrate to produce proper temps. and UV exposure.

I would be more concerned about how many microwatts of UVB per cm2 @ 1ft. the lamp radiates, rather than whether it's a 100w or 160w spot or flood.
-----
"A man that should call everything by it's right name, would hardly pass the streets without being knocked down as a common enemy." The Complete Works of George Savile, First Marquess of Halifax 1912,246