9447 vs 9449 is a personal preference, check out their specs here: http://www.red90.ca/rovers/springinfo.html
The 9449 is just 50lbs/inch stiffer for carrying more weight.
MOST people use stock replacement struts (ie, anything you can find on rockauto), with the OME being the only true aftermarket struts available. If you really want to take a deep dive into struts, you could research some of the other Australian companies that make struts with their lift kits, and see if you could coerce them to ship over here. I’ve yet to see that done.
Top out varies from ride to ride. On My AC/KYB front setup, I don’t have any complaints (it is certainly stiffer than the OME coils though) and many of my friends who have done the same also like this setup, but I know other people who are not as satisfied. If you’re not 100% set on them, consider a dobinson or OME 2928 front setup, those are great coils, and if they’re too short for you you can pretty safely add a 1” spacer after they’ve settled.
Correct on the 33-185552. You need to swap one of the bushings, or (at your own risk of damage to the bushing) use washers and clamp it down so tight it doesn’t move. The obvious, better choice, is to locate a new bushing. I’m not sure where one does that. On facelift R50’s, you can swap the bolt on the upper mount, I’m unsure of the same option is available to you on the lower mount.
compressinng the AC coils without a professional spring compressor is usuallly sketchy, I’ve yet to see anyone try the AC coils with that specific tool, though I’d be optimistic about it working. That tool has been used very successfully to compress OME coils.
Hope that helps!