In reply to Sam W:
We Pay out on call operational support guys and girls just shy of £100 per day This covers 6am until Midnight.
The full time base we pay is higher at £38k but its a skilled niech support roll.
We stopped combining the roll with people who worked for us 9-5 because if they got disturbed a couple of times in the night they were generally rubbish at work the next day. Our support guys average about 1.7 out of hours calls a day. Our average time to resolution for a call is usually a couple of hours (we only get called when things get really messed up operationally)
Most of our out of hours support is now done my stay at home Mums and Dads who appreciate the flexibility. and as a business this approach has helped us retain staff who we would have otherwise lost and we now have some of our most skilled people in tech support, which our customer really appreciate.
At the end of the day you probably have a good idea of who in your team would take this on, think about what a reasonable hourly rate would be for the number of calls you expect.
All The Best
James