"First off my installer put in a simple 2 pole switch between the G terminal and the R terminal of the thermostat blockl on the chip. What is the purpose of this?" Ask The Installer.
Upgrade your wiring to at least 5 wires for a heat pump. One day if you want AC, might as well get a heat pump, depending on your climate.
I do not know the type of motor you have in the furnace so I can't tell you if it's easy to make it give you more air flow. You might want to check the wiring diagram of the blower. Usually the blower speed for heat is different for AC/FAN only. Maybe that's why the tech put the switch in the G/R circuit. If your thermostat does not have a FAN Only switch, the switch the tech gave you may be a substitute. Again, ask your tech.