The higher the charge rate is, the better the charger should be.
So in many consumer products (shavers, toothbrushes etc.), the charge rate is quite low, thus they can produce the charger cheaper !
But... you got an high end charger
And your batteries are made for these high rates
So you can safely charge your batteries at much higher rates ( if your power supply supports it
This will both save a lot of time AND makes your car way faster. The higher amps, the more punch you'll get out of your car (at least to some extend).
I'll say: Charge your GP's at at least 5 amps. On this site, Promatch (who match batteries for living) have som recommendations. Promatch
Your TX pack: Divide the capacity by 2, so 3-400 mAmps. If you're in a hurry, go to 0,73 amps.
The single cell: It'll depend on brand and purpose, but with the same rules as for the TX pack, you'll be on the safe side.