Any advice for changing rear wishbone?

[fourcircle]

there's a full guide for changing suspension on A4mods here but I just need to change one rear wishbone. one of the "tabs" on a RARB drop link snapped and on the opposite side the ****ing bolt snapped. So I got a new drop link, got under the car and drilled a hole into the bolt, got a stud extractor into the hole but snapped the ****** when trying to get the bolt out. so I tried drilling tiny holes around it, tried drilling the bit out and inevitably made a ****ing mess of it. So ordered a new (well.. used but good nick) wishbone and have it in my garage to fit now.
The rear spring sits on the wishbone independently of the strut so I need to find out how much pressure is needed to push the wishbone up (and what force to expect when taking the old one off). I'm currently thinking that I need to get the car up on my big aluminium garage jack and axle stands and then use the small jack to lift the hub carrier assembly up, disconnect the wishbone from the carrier and then then lower gently to release the spring's tension. and then the same in reverse. rear bolts on and then jack it up slowly into position with the spring in place. Looking at the A4 mods guide I'm wondering now if I need spring compressors too, to hold the tension in the spring while I change the wishbones over.
This really is a lot of ******* about because of a snapped bolt. I'm not keen on giving a local mechanic a load of money to do it at his leisure though (and then do the "ah yeah, tool ages, sorry. that'll be a small fortune please").

 

[fourcircle]

the answer to this is... don't try. after undoing everything I got stuck at the innermost bolt to the front. with the nut off the bolt needs to be pulled out towards the front of the car and there's no room as the fuel tank (or something else encased in layers of plastic and metal) is in the way. Even with the subframe partially dropped down it didn't work. So eventually I put the innermost 2 bolts and nuts back on loosely and removed brake calliper, disk etc and drilled through from above to where I had started below. So now my drop link is held on with one normal bolt, threaded into the wishbone, and another bolt and locking nut right through the wishbone. Reasonably simple if I hadn't had to take apart the whole corner, compress the spring etc.