The reflector in the pic above is only a cheap model which i found created hot spots mainly where the bulb screws into the bayonet fitting & this being in a localized area below said point which damaged leaf tissue & dried bud out to a worthless point of being binned in the focal point off the heat spot !
Hence a diffusser was used too stop problem which it did do successfully
How ever fluffy or airy nugs of bud is not every body's cup of tea my ol china !
So i up graded my reflector to a better design & not looked back since.
Most standard hood designs do create a hot spot some where with some being at a more focused point than others !
So ye its really down to finding optimal hanging point of hood with said sized bulb of what ever wattage & if ya getting burnt bud then its to close
Or ultimately look at at cooled hoods which can be hanged a lot closer increasing effective light energy & in theory increasing mass of bud... but ya should really clean glass of air cooled hoods after each grow as dust/dirt build up may diminsh light quality & over time lower mass of bud if ya a lazy cleaner !