I've used all three methods installing HS-- hammer and block of wood, threaded rod and washers, and Headset press. You can mangle the job with any of the three, and you can do it properly with any of the three. I prefer the last; it is easiest.

When installing, simply take your time and and be sure the cups are going in straight.

I've installed crown races succesfully using a piece of PVC pipe as a slide hammer. It's not difficult.

However, if you've not done it before and have spent beaucoup $$$ on the frame, take it to a shop. They'll likely overcharge you. You could also buy a junker frame to practice on, then do it for real.