smwelder,
I don't know if my type of ceiling hoist would work for you, but I will try to explain how mine is.
Steve (husband) made a ceiling hoist for me in our small 2nd bathroom. The aluminum I-beam runs from one end of the bathroom to the other end, which ends up straight over my tub chair where I am lowered.
1st- While my chair and I are stationed in the hallway, He puts the sling in place around me. Then I drive into the bathroom and go in as far as I can (which is right below the I-beam that the hoist is attached to). He then hooks me up, raises me and it is a straight glide to the shower/tub. He lowers me right on to my tub chair. All the parts cost around $500.00. The hoist, trolley and I-beam will withstand far more weight than what you weigh.
He originally hooked up a manual hoist, but now has substituted it for an electric. Both are very easy to use. The electric one is like a toy for him. Zoom, zoom
I have downloaded photos.