use centerstand
I just did this a few days ago for my 75 Mark 3. Replaced the old lines with braided steel lines from oldbritts - look much nicer.
I tried with a jack stand, but no go. used the centerstand, but with a small square of plywood under it to get it up a bit higher, so i could get underneath easier.
Yeah, you have to unbolt the fitting for the oil filter, attach the lines to it, then push it back up , while using your other hand to guide the lines up in the right routing.
Good luck!!