You get good at it! I used to do the bottom engine mounts for people for money (not a mechanic) cos I got good at it. It is a right fiddly little pain in the arse but if you know how to do it and have exactly the right tools it can be done quickly without disconnecting anything else. Getting the motor/trans out is also easy too after you have done a couple. I had a thick nylon rope with an eye at each end and a fence strainer, which is up for the job and way quicker than an endless chain. As it comes up you just roll it in the rope sling, easy! I will put my hand up for this too! A gigglin' and a jigglin'
I followed this man in the early days watching his stock and he just gets the best mini's ever,but at premium prices. https://www.rwclassicminis.co.uk/classic-minis-for-sale/
If you want to look at some really nice Mini's check out the ones that one of our customers build to order https://www.davidbrownautomotive.com
Early cars had a small amount of toe-in as std, I can't remember how much it varied over the years but 3 mm comes to mind.