you can make a poor man's impact driver by taking a screwdriver and tap it with a hammer as you turn it. that might help.
i replace all the hardware with grade 8 allen head bolts as soon as i open the box.
instructions are available online somewhere...
...here's one from zone 8: bicycle engine kit installation
i didn't read through it to see how accurate it is, but it sounds like you've got most of it figured out.