naio, if you have the skill and tools to properly solder 6awg wire, I say just continue that route.
Don't know about ratcheting crimpers for upto the 10 AWG terminals, but my hydraulic harbor freight crimper is not a one handed device. The last few compression strokes as the lug and copper stranding are at the limits of compress-ability, I use two hands and the strength of my arms to make the dies touch.
So the hand strength is not required as much with the Hydraulic crimper, it is more about dexterity to hold the lug inplace as one moves the arm closer to touch the dies to the lug, and hold the wire in place while getting those first few compression strokes in.
Once the lug is compressed enough for the wire to not fall out, I then use two hands, one to hold the tool and the other is on the handle to lever it closed. More arms strength required here than hand grip strength.
There is some awkwardness in the process of getting the Dies to hold the lug, and then holding the copper wire in place and then cranked down.
Lugs are too expensive for mistakes and redo's