Radiator transmission lines/coolant flush

'97 buick Skylark V6 3.1ltr

the radiator has a line at the top and bottom for transmission. i am going to flush the system and am supposed to attach a clear hose where the tranny fluid goes back to the transmission. so is it the top or the bottom?

Should I switch from orange Dex-Cool to standard green?
I have read that Dex-Cool is corrosive. Though maybe they have fixed it from the old versions?

If I should switch.
So there is a hose that goes from the coolant reservoir then 'tees' to the bottom of the radiator and to the wate pump. Then there is a hose on the other side about halfway that I guess comes from the thermostat.
Since my heater core has been bypassed I am not going to get a kit.

I am thinking just keep the reservoir filled with the radiator hose on the thermostat side unhooked and run the engine until the water comes out clear.

thanks for any info.

Ok
Replaced the radiator, flushed the collant and transmission and replaced the filter. No problems.