Dre and Timbaland use anywhere between 70 and 100.
Double time and time and a half can actually be useful in a track, just knowing math to convert back to your original tempo, and you can do some pretty tricky hi hat, snare, or kick rolls.
These have to be accomodated by other variables, like double time needs to have twice as many steps, instead of 16, you need 32. time and a half is the same, you need 24 steps.
This can help out when doing a 90 bpm track and using a 135 bpm snare and hi hat track with your other instruments.
Just make sure you make the 24 steps into forths, (if you're using 4/4 ts, which i assume you are), instead of 4 steps a beat, its 6. In double time, there are 8 steps a beat. If you dare step to triple, well, you're dealing with 48 total steps, and 12 steps a quarter note ( a beat = 1/4 in a 4/4 ts arrangement).
So in triple time, a 90 bpm track is 270 bpm with 48 steps. The time is takes your 90 bpm track to get through a beat ( quarter note, 1/4) of 4 notes, it takes
the tripled track @ 270 bpm the same time to get through 12 steps, giving you three times the amount of samples to trigger in the same space.
You can also just go into thirds on the sequencer, but its easier with full steps.
If you have questions, drop me a line.