What feels like the cranks skipping a beat

the "walking method" check sheldon's website, basically involves, having one track nut tight, pulling the wheel to one side, tighten that side, loosen other side, pull that way. in this way the wheel "walks" in the dropout, enabling perfect tension. when in correct place, make sure wheel is centred and just tighten the nuts down.

you don't need a lockring tool to put a cog on?

True, thought might be being lazy and calling a chain whip a lockring tool, but it appears they are just being idiots!