We operate in Europe about 600 hours/year/aircraft and use very little TKS. I have found that crews new to the aircarft think they need to run the TKS every time they go into cloud (even in the cruise!). That is obviously not necessary. Proper use should see annual utilisation at about 250-300 litres per year. One only needs to use the system when one is in ice forming clouds.
As far as range is concerned the best Hawker is still the 800 non XP without reversers. Depending on temp and pax load we get 6.2 - 6.5 hours at 410 Knots landing with 1200 lbs...hard to beat and only cost 1/3 of an 850 XP!! Record is 7 hours and landing with 1000