This is exactly the way I have my 2004R lock-up wired (manual switch). My trans shifts into 4th gear at about 45 mph... but I do not engage the lock-up until I am above 55-60 mph. I also run a very large "stacked plate" trans cooler.Added a simple manual on/off switch to the control circuit. Now typically engage the lock up above 55 mph.
If you like having the lock-up functions controlled by the brake and vacuum switches and don't want to have to remember to manual lock-up the converter above a certain speed (and manually disengage when you drop below a certain speed), you could add a B&M controller to your existing set up that would let you choose the mph that the lock-up function on the converter automatically engages/disengages.
The B&M converter lockup controller provides dash-mounted control to govern converter lockup at any speed between 30 and 90 mph. These kits eliminate converter lock and unlock cycling and premature unwanted converter lockup.