Temperature should be cool - if it's too hot they just won't grow. Around 20C (68F) or so seemed pretty ideal for me.

• The average outdoor temperature is 25C (77F) now. We had an unusually hot summer this year with endless heat waves so my outdoor Haworthia were not doing much. The weather cooled down for almost two weeks (as of last week) and nearly all of them started to sprout inflorescences and new growth now.
• The average indoor temperature is 28C (82F) now and only a few of my Haworthia are flowering. They show the best growth spurts around 23C (73F) or lower, which I can tell because it depends on how low I set my thermostat and for how long. =)

Light intensity should be bright, but not too much. If they get too stressed and turn too reddish/brownish/purplish, they won't grow as fast. I find this can be quite tricky to balance.

• The average DLI for my outdoor Haworthia grow area is now around 13 mol/m2/d (6000ftc / 63klux). I think this reading is a little low as I placed my sensor closer to the wall so it's easier to collect the data. This seems to be a good amount outdoors, considering the heat levels (which peak up to around 35-50C during the day and 15-20C at night).
• The hot daytime temperatures affects their growth. However, I find the night temperatures most critical in ensuring good growth.
• The average DLI for my indoor Haworthia grow area is now around 36 mol/m2/d (15.8kftc / 171klux). Although the average temperature in my home is cooler, the night time temperatures are not as good (33C peak, 24C low).
• So I find this hasn't triggered them to flower so much but is proving to be good for growth.

Duration of light isn't something I've played with too much. My timers are kept in sync with local sunrise and sunset times.

• I find that temperature and light have a bigger role in Haworthia than light duration.
• However, other succulents such as my Mesembs are quite responsive to day duration and their flowers open/close in relation to that.

Hopefully that helps give an idea? The numbers aren't that important really - that's my own growing conditions and what I've noted to correlate with periods of good growth.

I think there is a lot of flexibility in growing conditions and it's up to you how you want to tweak or take advantage of them (or not, which is a perfectly acceptable choice too).