Well, I’ve finally made my decision too – after umming and ahhing about whether to buy the second tent (good reasons provided here for and against) and then the size (bivvy, two man, one man) I’ve decided: yes, I’ll buy another tent and it will be a MSR Hubba Hubba HP (slightly larger - interior and vestibules - and lighter and has less mesh than the Moondance 2). Although expensive here it’s very competitively priced in the US (around $400USD). I did also consider the Nallo 2 (I’m tall for a girl – 6’1” or 185cm depending on whether you’re imperial or metric – so I guess would “fit” that) but really prefer the 2 doors/vestibules – I generally hike with someone else. (However, if I ever feel the need to add a 1 man to my arsenal, the Hilleberg Akto will definitely be in my sights! Nice!).
N.B. I would’ve considered the new Macpac Macrolight too if there was more information around about it (exact specs, cost, pics) and I knew for sure it would be available for the next major trip.
The Olympus is starting to get towards the end of its life. To maximise that, I'll use that for trips that require a 4 season tent (have done some snow camping in it – loved it and would like to do some more – that’s what it was originally bought for) or where there is a shortish walk to a base camp; and use the MSR for more extended/move on each day 3 season hikes.
‘Thought briefly about the bivvy again but if I am honest with myself the only time I would use one would be as a back-up when using huts.
Brett, thanks also for sharing your justification for gear purchases – tent versus hotel room costs – I like the way you think! Now, if I can just find a similar justification for my other gear purchases …

Re the knees – I’m mid 40’s (ain’t old at all Paula – except for those much younger than us!!) and alas, I can’t blame anyone but myself!

Paula, yes I’ve done a few sections of the Bib but not as much as I’d like to! (Yet). When I was still living in WA (and for the first 8 years here in Sydney – I’ve been here 15 years) I travelled a lot for work/sport and had little time for hiking. I’ve been making up for it since!
Just two last questions…. we’re going to the WOJ (amongst other places) in November. Is there a need to treat drinking water there? Is a -5 bag recommended there (as per OT) too?
Thanks very much for your help – this is a great site!
Cheers,
JB