T1 is easy to skid wide on, but it's a great corner, imho. T1, 2, first chicane and the two righthanders after the second chicane are my favorites. T2 exit in a Panty is awesome, as long as you don't care about hotlapping or mind leaving your tires on the pavement
One key point to make time on Zolder is using a good chunk of the grass on the left going into the first chicane. Almost sorry to say it's worth at least half a second, maybe as much as a second, at least compared to keeping all tires on the asphalt.
Second chicane you gotta brake fairly early to make sure you don't drift wide in the first right, so you can get on the gas as early as possible going out of the chicane, just staying off the sand, but definitely using the concrete or whatever that grey stuff is (for rank hotlapping, not UKGTL legal). Actually, it's not only about getting on the gas early, since you also have to position yourself away from the right side for the following righthander.
Hairpin obviously be vary of going wide, only think about getting on the gas as early as possible. Third and final chicane again make sure you don't drift wide on the lefthander, stay on the inside of that to get a good line through the righthander for good speed on to the start/finish straight.
I don't recall exactly, but I'm fairly certain that achieving GTL rank times means cutting chicanes a good deal, at least the second chicane so all tires are outside the white lines, which of course is not allowed in UKGTL.
I should do 55's in the Alfa on a good day, and the rank page says my PB in the Falcon is 56.9. But, I haven't driven on Zolder in ages and keeping the lap UKGTL legal I'd say, and this is a pretty wild guess here, maybe high 56 in Alfa and Falcon a second slower for qually. Full tank or worn tires add another second. Maybe more, maybe less. If Bara or Ruskus practice, well, best not speak for others