I posted a question in Stack Overflow about making custom Google maps. Should I ask it here?
Your questions seem to be about GIS, and in that sense are certainly on-topic.
However, if posted in its current form I would expect your question to be placed On Hold because:
- It contains several questions whereas our Tour is upfront that there should be only one question asked per question; and
- For questions to be answered here they should as much as possible describe not just what is wanted, but precisely what has been tried and where the asker is stuck trying that.
I would encourage you to post on the GIS Main site, but to review Asking good Questions for GIS Stack Exchange? before posting there.