I guess I'll have to try the screwdriver...
Couldn't say exactly how much I got on but reckon it was closer to 500m, maybe less though.
I wound 1 wrap of insulation tape directly to spool, then uni knot braid over tape, small piece of tape over knot.
I do remember the knot sat pretty close to the bottom of the spool, where should it sit & is the uni knot ok?