There was a post on here from a Tiger owner about the same thing. I have rigged a hoist for my H16 when I had indoor storage. I will try to describe it here, but let me know if you want a sketch.
I used 4 slings (2/hull) and was able to spread the load across 4 joists. WE will say in your case 100lbs per joist worst case. I weigh more than twice that and have walked around on ceiling joists many times.
I did use a block and tackle system to make life easier. You don't need ultra expensive components. We are only talking 400 lbs total weight of the boat. I sized mine by line diameter. You might even be able to find some at a hardware store. I bought a bunch of used ones on eBay.
I will describe how to reave on of the two hoists. I am assuming the hulls are running parallel with the joists (this system will also work with hulls and joist perpendicular). The idea is to have the hulls as close as possible to being in between 2 joists. It doesn't have to be exact. You can also skip a joist for better spacing.
Take a block and put it on each sling. Then, working across the ceiling put and eye bolt into the joist furthest from where you want to stand while hoisting. This is where you will tie the end of the line. Next place an eye bolt on the joist that will be on the other side of the first hull. Move to the joist that will be on the far side of the second hull, place an eye bolt there and finally finish up on the joist that will be closest to the hoisting point with another eye bolt.
Starting from the first eye blot, tie the line to this one. Then feed the line through the block on the first sling, up to the second eye bolt, next to the third eye bolt, down through the second sling, and finally through the fourth eye bolt. You are now ready to repeat this procedure for the second hoist. When complete, move the boat into position, find a helper and hoist her up. I put some cleats into a wall stud to tie it off.
Some notes: I only used block on the slings. For my H16 the weight did not create enough drag on the eye bolts in the ceiling to warrent the money for blocks up there. I woudl suggest you buy the extra blocks in case you need them. Try it without them. If you need them, great. If not, just return them.
I added an extra block to the joist closest to the wall I tied the hoist off to and ran the line through this. This kept the line up near the ceiling and out of the way.
If you use this set up where the hulls and joista are perpendicular then your eye bolts will be diagonal from each other on either side of the hulls. Remember to position your slings such that no two eye bolts will use the same joist.
I hope you get the idea. It's difficult to describe in words. Let me knwo if you want a sketch.
In the market
Previous boats owned
'74 Pearson 30
'82 H18 Magnum
St. Louis, MO