Shop Improvements: Overhead Hoist

To some this may be old news, but this is the first I have to post about this (to me, rather important) shop upgrade. For Christmas my Grandfather gave me money, which I spent on this 3-ton chain hoist; an invaluable tool for any sort of heavy automotive or small engine work, or any work that involves lifting heavy objects.
The hoist itself is a reletavely inexpensive, "Made in China" tool that, despite it's origin, seems to be of comparatively good quality (though it is in no way as good as a name-brand "Made in USA" hoist it was a far more cost-effective tool for my needs). To it I added a chain bag, which as you can see is made from a pair of bread bags! The only other alteration I made to this hoist was to paint the lifting hook safety yellow, which makes it more visable (and therefore less likely to be hit by accident).
The hoist is currently mounted to the rafters by a 7-foot length of 7/8 inch SAE 1040 bar stock, purchased from Innovative Tool and Die. This bar contacts four beams, and by my calculations (judging from seeing a 200 pound man stand on one beam without causing any visable deflection, and having used this hoist to lift a 450-pound locomotive cylinder head whilst supported by a lengh of pipe contacting only two beams)I'd judge it's maximum safe load as-is at 1,000 pounds. This rating more than satisfies my needs; I could use it to lift an entire lawn tractor, or any automotive engine without trouble.
Needless to say this is only a semi-permanant installation. Though I have load-tested it I don't like the idea of using the rafters to support weight, however for the moment I have no choice in the matter. Eventually I plan on mointing an I-beam to the rafters and supporting it on both ends with pillars, and adding a trolley to my hoist arrangement (which allows the load to be moved along the length of the beam). However at the moment what I have will need to make due. I plan at the very minimum to reinforce the rafters and to shim the support bar to help even out the loading before I use the hoist to lift over 400 pounds again...