You can reduce the speed of the servo by setting a Speed limit in the Channel Settings tab of the Maestro Control Center. The speed limit tells the Maestro how fast it is allowed to change the pulse width.
There is also a Set Speed serial command you can use, which is documented in the Maestro User’s Guide. This would allow you to change the speed limit on the fly from your basic stamp.
Are you really using 84 baud? Typical baud rates are around 9600 - 115200, so 84 would be extremely slow. You should use an actual delay/wait/sleep function if you want your program to run slowly, instead of using a really slow baud rate.