Bridge cranes from a kit. Any experience?

I am considering installing 2 of these. Harrington HPC500 Medium Duty Class B Cranes, 1 ton kits. These kits have the end trucks and bridge complete. Just need long runners and hoist with hoist trolley. It just seems to make sense for the $ involved. These are not powered in either direction. 2 of the 1 ton units in 12 foot will do more than I need but I have some questions. I would like to use a 16 footer for one space but the ceiling rails would be a max of 11 feet apart so the load at the ends would be cantilevered. I can compensate with extra rollers for bridge tilt but do not know just how accepted this is. I do plan on talking to the manf direct first.
Long rails will be hung from the ceiling beams. The longest section has a Southern Yellow Pine 12 x 12 every 10 feet, they span 24 feet for the floor above. The section that I want the cantilever located wouls have the ceiling rails running the same direction as the pine beams, hence the 11 foot spread.
Any thoughts?
Thanks

For that size I would think the bridge is just a piece of beam with some bolt holes at each end. Seems silly to pay shipping for that. The trucks yes I see.
Bill D.

I'm no engineer but I question if 12x12 spanning 24' would be enough to hold a 2,000lb load plus the weight of the crane.

I don't think the cantilever would be to big of deal, at long as the rails were supported good. You are only talking about 2.5 feet on each end.

I worked for 11 months fabricating cranes and end trucks. Normally overhead cranes are supported by a structure that is separate from the building. As soon as you incorporate part of the building you are in a dangerous place.

Thanks for input so far. This is a WWII era mill building and the ceiling beams are most likely first growth yellow pine, hard or harder than oak. 12x12 is a guess as they may be even larger. Cannot drive a nail into it. They support the floor above and there is very little (as in none) loading above. Maybe good idea to think about how I attach the steel to the beam. I need to think of a way so that the steel below acts as a tension member to increase stiffness. This whole system is necessary but sees vary little use, and to date the single rail that is supported every 10 feet has not even seen 1000 pounds. The complete bridge kit is somewhere around 900 pounds, trucks and beam.

Freight may cost a bit more but I will end up with an engineered product (sans long rails) that will have some resale value in the future. Hoping freight will be less if I buy 2 kits.

Wow, just looked this up. Going ahead and even though the ceiling supports are 10 ft cl to cl into SLP, the supports are located just 2 feet from the end of each column. They are 24 foot total span and runway will be 20" cl to cl. Harrington Hoist end trucks. Runway will be S8 and bridge is S10. One ton max load but most will be a lot less. Going with push trucks at first.
Power runners most likely will be Conductix Wampfler (spelling)