Help! Simple question on wiring the pros would know

I have an older model trane air handler, I'd say probably 1995 installed. Works pretty good but it didn't have the common line (B) wired. I'm no expert so running a line isn't a thing I can do because I'd never be able to figure out how to run it through the walls, etc. So I read you can switch your G line to the common line on both thermostat and air handler. Doing this removes your ability to run fan only, and for those of you that know Florida, that's not a problem since we never run the fan only! I want to know if this is safe to do? The thermostat website said if I do this, I will then need to jumper the G and Y line on the air handler so that the fan turns on when the cool call comes in. My question to you, is this safe? I don't want to burn anything out so I wanted to make sure ahead of time before I do it. It's HOOOOOT here so any guidance you can give would be greatly appreciated ;)

Help! Simple question on wiring the pros would know