Too low, need advice making it a daily driver

[VTX-Black]

While I have been building my own stuff, my wife went out and bought one already done. Problem is that speed bumps etc make it impractical and she wants it raised a bit. (Wheels also rub inner fenders and I don't want to modify the fenders).

Here is what it looks like now.

What I am looking for advice on is:
1) advice on how much higher to go and
2) the best way to do that without too much trial and error.

Since I didn't build this one I am not sure how much drop the spindles have etc.

Thanks
Wayne