The question of whether it also supports the building framing is an important one, because the point load which causes it to deflect would then also deflect the building structure by the same amount. Seems insignificant but is the building elastic enough to dip by 3/4" in the center?
Imo you are better off making your hoist beam independent.
If it was me, I would use a W8 x 24, but you have to ask yourself if you are equipped to handle a ~600# unwieldy chunk of metal that has to be tightly fitted into the confines of an existing building? A practical problem buried in there is you need to be able to measure and cut it to 1/16" precision, and potentially do some high-confidence structural welding for attaching plates.
The problems to be resolved continue because appropriate connections have to be made to columns (could be tube-steel, bolted flanges) and the columns have to be supported in 2 directions viewed from the top so they don't fall over while loaded. Using wood columns makes this more challenging as knife plates have to be designed with clearance for heavy hex bolts. The side loading is especially important if the load is trolleyed on the beam which is quite likely in your setup. In one direction a "knee brace" could be used, but the other direction is likely in the plane of the wall. Metal "X" bracing would be my choice to add a little more racking resistance to the wall plane.
Actual paid engineering services will give you a practical plan to build from. I can tell you about the issues but am not qualified to actually design the beam.
The people suggesting a gantry are giving good advice, I will add to that, make sure you design the "parking area" for it because it will likely sit around 99.9% of the time. Allowing it to straddle over top of an existing workbench is usually a decent plan if there aren't swinging-door cabinets mounted over top of it.
This is for mainly for supporting the roof and not specifically for lifting although the designer put a slight bit of oversize....
