It 1ml per 33kg of pig.
Jabs are sub-cutaneous(ie under the skin) usually between the neck & the shoulder.
As i said i just ring the vet and say i want a syringe making up for me to collect but if you have dectomax for sheep you can use that, at 10wks old 0.75ml should be about right but if you gave them a ml it wouldn't do any harm.
HTH
mandy
Ps the kids will have great fun, we use tepid water in watering cans to damp them, then shampoo them and make sure rinsed thoroughly, if you use a hosepipe don't have it on jet it frightens them and the cold water is a shock, just think how you like to be showered!