Probably the hardest/worst job I ever did was changing the clutch on a friends Vitesse on our backs under his car without the clutch alignment tool - outdoors whist it was raining. He lived near Ilkley in a rented cottage. No trolly jacks just chunks of wood, a scissor jack & bottle jack. He had assembled the clutch before I arrived all we had to do was slide the bell housing/gearbox into position and nip up the housing he said - easy as you could reach stuff from inside the car.
We struggled for almost an hour before I insisted we removed his new clutch & checked it against the old one - yep wrong one.
Trip into Bradford to change the unit for a genuine part at double the money - it went on first lift when we had the right clutch - there was a lot of swearing then smiling when it was done. We both had skinned elbows & bleeding knuckles when we went for a pint afterwards.
Happy days though.