I don't do crawling around under cars any more. 2 post hoist was the best investment I'd made in ages.
Mine is a 4 ton clear floor 2 poster with asymmetrical arms. Bought it from Radum.
If you do go for a 2 post I can recommend a clear floor style. If you are wheeling a trolley or anything under your car you will have a nice clear run. Remember for a lot of the time you will be pushing your car onto the hoist as you build or work on it. Not having to get it roll over the cross cable hump will make life easier too.
You do need a bit more ceiling height with the clear floor style. I think my shed is 5.5M to the peak but the hoist is about 4M tall from memory.
Welcome aboard. Post lots of pics. We love shed builds too.
Cheers