A "proper " ($75.00 or so ) crimper is claimed to press the terminal enough to cold flow the copper and make the terminal end air tight.
Perhaps , but covering it with shrink tube still is a great idea , the color helps when doing the hookup pr trouble shooting.
Large sized wiring like starter wires are usually long term requirements , so can be ordered on line with well connected terminal ends.
The hassle is wires thicker than a hand squeezer , but not of starter size.
A crimping tool made for swagged life lines or 7x19 rigging will usually handle terminal ends for wiring that is thick .
These will take 4 sizes and are under $30.00 , even at Worst Marine.Tighten 2 hardened bolts to swage.
On large terminal ends even a 5lb copper roofing iron may be hard pressed to do a good solder job.
Then its time to find a cast ladle or pot and simply dip the end into molten solder.
A common (cheap) euro practice is to dip un tinned copper wire for 1/2 inch or so , that it can be captured under a screw head.
Not great but pretty common on lights , switches and radio stuff.