Straighten a leaning garage

[Chris E.]

I have a leaning garage on a property I just bought this week. It seems to be leaning because the garage was built in front of a smaller work shop. Instead of building the garage and making a doorway in the back to connect the two, they just built the garage without a back wall, so its just two side walls and a roof that has slowly shifted over the years. My plan is to use heavy duty 9000lb ratchet straps to pull the garage over. One at the front and one at the rear.  and then ad a half wall, with  well anchored sill plate on the floor to square it up. Heres my plan:

1. Mount a 6ft long 2x6 on the outside top of the wall on the left side, screwed to 3 or 4 studs.

2. Run a through bolt though the board, and garage siding/osb into the garage

3. attach ratchet strap to through bolt

4. attach other end of strap across the garage to through bolt on another board which is mounted to the floor using two 1/2 inch concrete anchors. (the kind that you drill a hole and then hammer them in the hole roughly 2 inches deep, rated for 3500lbs a piece)

Only real concern I can think of is the fact that Im pulling over and DOWN instead of just straight over. My dads idea was to use the same method only instead of pulling to the garage floor, he said to use the inside wall on the house to pull from and use 2x4s anchored from the wall studs to the floor joists to secure the wall. but id rather not use the house. It has a very old floor that already needs to be jacked up in areas due to sagging and I dont trust it. 

Anyone have any similar experience they'd like to share with fixing leaning buildings?