i think If you do everything 10-15% is a good cut for the owner
for example £1000 worth of good paying customers you clean it and each month you pay him £150.00 collecting your responsibility along with everything els.
how it worked for a friend of mine was like that, also the agreement they had was any work lost that meant cancellation of any means his bad work or just cos they dont like him ment he would need to pay the round lord 3x clean so if a £10 house cancels he would pay him £30 extra but it worked the same the other way too say he picked up £50 he would not need to pay him any rent cos it was £50x3 made the rent that month.