I done it years ago, during my university holidays. Rubbish job. We didn't get a set amount of target installs or service calls, just whatever were available on the day. I wasn't directly with Sky but a installation subcontractor. Don't even recall the name but based out in Essex. Run by two typical Essex thieves.
You'd go in in the morning, get your job sheets, STBs or whatever you were doing on the day and head out. If you know anyone with Sky for the past 15 years in Chafford Hundred (spelling?) or Grays, chances are I done their install. I'd do about 3-5 installs and the same amount of service calls and got paid per job completed. Although there were days I'd do up to 10 installations and work till 9pm in the evening. Service calls were quite good as we got paid quite well per repair (can't remember amount) but the only PITA was that you sometimes had to take money directly from the client. Standard charge were £75. Naturally being in armpit of Essex sometimes people didn't have the money. I was offered 'services' from women on occasion to fix their Sky when they couldn't pay.
Some houses were so filthy you'd itch walking out. I've installed in a gypsy caravan camp. In nightclubs and pubs. Real mixed bag. At time quite enjoyable but it's not a career, just a job to tie you over. That's my opinion anyway.