I can't help - but it does make me wonder about the payload.
I thought the R22 had a seat weight limit of 200lbs (or is it 225?).
If it can't carry sufficient fuel for an hour flight plus reserves, an examiner of greater than 11 stone (154lbs), and a candidate who must be below 201lbs (or 226lbs) by definition, then what can it do?
What's the fuel burn? Simple piston and no time to Google I would guess at 7US galls per hour - so...
7 x 6lbs = 42
3.5 x 6lbs = 21
candidate 226
examiner 154
443lbs
Can't it do that?