Your Internet provider can figure out you do easily as messages aren't encrypted. In that case, you should just run via Tor.
This is important.
It's 'easier' and 'more convenient' to run without Tor, however it is best to do so especially if you are hosting from home. A rented VPS (no matter how privately it was acquired) might be more flexible on how important it is though it's not a big sacrifice to achieve privacy.
A VPN + Tor is just a good way to add an additional layer to the system as a whole, though I don't believe this will make a lot of difference in regards to your node. It may require further configuration to prevent connectivity issues.