The difficulty is that none of the rides at thorpe have any sort of decent capacity to hold a really good working reserve system (or free fastpass system).
If they had rides doing 2000pph, they could allocate a good 1000pph to the fastpass and it'll be absolutely fine, lovely.
Instead they have rides (if we say now they've included flats) which can do 400pph... so even 50 people using reserve will make a big difference to the main queue.
Fuuuuun. May as well change to Qbot if they wanna do this (oorrrr stick to allocated fastrack timeslots, of which you'd make far more money even when managed properly unlike a revenue share Qbot!)