Does anyone have any input into how best to install and hang anchors into the ceiling studs? I'd like to hang a hammock. I'm assuming a single stud will not hold the weight of a person so I probably will need to carry the weight across multiple ceiling studs. What would you recommend for hardware and design?

The roof structure is plenty strong enough to support the weight. If you have any doubt get up on the roof and jump up and down on the roof cross members.

It would also depend on the size of the person(s) using the hammock also. I like Doorman's test, but then again the ladder to the roof my be only rated at 200 pounds or so.

You need to google "the difference between "compression" and "tension"". The fact that one can jump on a roof truss is not the same as pulling a fastener through an 18 gauge aluminum U channel. As an example, the pull down bed in the Euro is attached to blocks of wood squeezed into the space between the trusses to spread the loads. In order to work you would need to transfer the load to the top of the truss, placing the anchor in compression rather then pulling down on the bottom placing it in tension.