Been in Westwinds for the last ten years. Here ya go.
Fuel burn:
Hr. 1=2000lbs
Hr. 2=1700lbs
Hr. 3=1500lbs
Figure about 200lbs for Taxi if on both engines.
Long range cruise avrg constant speed is about M.70.
2000lbs is a pretty standard IFR reserve with about 1800 being a VFR reserve.
Will do ATL to SFO non-stop once the winter headwinds die down. With a 2000lbs reserve at constant M.70.
However, you'll need the runway to do a flaps zero T/O due to the lack of second segment climb performance on the warmer (above 85F) days if you're at or above 1000ftMSL and maybe if you're at SL. The two has better second segment climb performance and slightly better top end speed, and also, most carry an extra 200 lbs of fuel which can make or break how you feel about a bingo point for a fuel stop. The II also has a tendency to do a slight "wing rock" once at altitude and it's just something you kind of have to get used to.
It has a high max gross landing weight at 19000lbs and also higher Vref speed for an approach, 131, at MGLW. This can cause a problem for legally flying some instrument approaches because it places it in the Cat D box. Most of the time, if that throws a wrench in the flying the approach in IMC, you might want to reconsider doing it anyway. Generally, 5000' min runway length for landing.
The Westwind flys "heavy" but is a stable platform. I think it tends to to fly like older, larger aircraft. Also, they are starting to get a little older and having more and more maintenance issues, in particular some issues regarding the vertical stab. Just have to make sure maintenance is thorough. Also, RVSM is going to be expensive, and a fuel burn below 290 would be ridiculously brutal.
Bottom line, there's not a better long range/high payload aircraft for the money. Lear 35, Falcon 10, HS700 don't have the range, and in some cases, the performance, i.e. "high and hot".
Hope this helps. Best of luck. I've enjoyed flying it.