What age is your DS.
I do a lot of odd hours, late nights and weekends away, but I am not full time, Kids are both at school.
My exMIL looks after them, and they stay over there. It is only perhaps once a week, saturdays and overnight stays once a month on average. If I was full time she would have to have them every night aftere school and take them to their activities, that would be the killer. There is no after school club here and she just couldn't manage.
I know someone who works night shifts but again not full time, she spreads her child care between her sister, brother and childs grandparents, so noone has her too often.
I think working full time plus the extra time is very difficult on your own.
A live in nanny is one option, but needs a bloody good wage and a big enough house.
Combining the childminder with a mature reliable babysitter may be an option but will still cost, perhaps a childcare student would be a able to do the those hours.
An aupair is a cheaper option but couldn't look after child full time, only usefull for much older children, so perhaps an option for the future.
I suppose its about weighing it all up and seeing if it is worth it, will you be able to reduce the hours in the future or earn more money?