Ignore my previous post (facepalm), Following the video, I just needed to compress the spring an inch or so before loosening the top nut.
Worked a treat. Hardest part was getting the LCA nuts loose, as well as the top nut on the struts (and shocks on the rear). Truck rides great now with the new Bilstein 4600s - a world of difference.
Oh, and about the sway bar - Was scratching my head about that, the bar end was getting in my way while installing the strut assembly. Took me a moment to realize that I should raise the other side of the truck to let the opposite wheel drop - that let the sway bar relax and gave me the extra bit of clearance.