I posted about exactly this situation a while back, and have been working on reducing my wardrobe ever since. Had I had time before the move I would definitely have done at least a large chunk of the edit before moving rather than waiting until afterwards, because when you are in a smaller space crammed with clothes and footwear, it is, at least for me (I like my space minimalist and so clutter-free that some friends consider it austere) very overwhelming. And yes, I do have a storage unit but this just makes me feel even more guilty, and actually it is a pain because it means that to get rid of the stuff in storage I have to go to the storage unit. Somehow, that is a real drag, and I wish I had not got the storage unit. Really, I just need to get rid of a vast amount of high-quality stuff I love. It is really not easy. Like you, I had very little remaining in the obviously-purge category, because I never kept stuff of that sort in the first place.
I did discover a few polyester items that I had stupidly bought despite the polyester because of the label, and I finally got rid of those. I also had some teeshirts containing elastane and donated those too, again because of how they feel. When I went through my footwear I found that I could get rid of several dozen pairs without having a panic attack, just by thinking about how much space shoes and boots take up and asking myself again and again if a given pair is so important that it is worth that use of space. (Put it this way, in addition to my overstuffed wardrobe I also have vast numbers of books, and for the first time ever apart from in the case of fiction, I am getting rid of books too, and now only buy ebooks, never hard copies, because every time I ask myself if I want to use my precious space for this book as opposed to having the same content on my iPhone, the answer is no.)
The trauma, for me at least, of not having a restful, clutter-free space certainly concentrates the mind but still I would try to make some choices and do some reducing before you move rather than waiting until afterwards.
WRT the system I have been using to get rid of high-quality stuff I love (ouch!), perhaps it is procrastinating but one thing I have done is to write a lot of (private) analysis of my style and lifestyle goals and the implications in terms of what I 'need' clotheswise, and thus, what I don't need. As part of this analysis, I tried to be super-critical, reassessing all my '10s' (out of 10) to see if any of them might be 9s or less if I took into account things like their flexibility in my wardrobe etc.
One new thing I discovered through this analysis was that I have quite strong preferences for heavier-weight fabric except for silk tops. This came as quite a surprise because I have a large collection of lightweight silk dresses. Or at least had. I have started getting rid of them. The guilt is such that I decided to wear each one before finally getting rid of it, and I might keep a small number of the ones that I (think I) love despite my realisation that I prefer heavyweight fabrics, because they take up so little space. In a rash moment of being off black (I was loving the pastel trend) I ruthlessly got rid of vast amounts of black stuff, but luckily not all, because I have started liking black again. I did this by asking myself which items out of all my black stuff I would be most upset to have lost in lost luggage or a house fire etc.
Incidentally, I tried having a colour consultation in the hope that that would narrow down the colours I think I can wear, but unfortunately it actually did the opposite, so that was a bit of a waste of money.
The one fun thing about this experience is that my new super-critical eye and the new knowledge I have about my newly-honed style feels freeing, and I actually can't remember when I last bought any clothes or shoes. Not only am I not shopping for clothes and shoes, I have also curbed all shopping for anything that takes up space, and this has been entirely without any feeling of deprivation. On the contrary, it actually feels good to be reducing rather than spending. I am reducing little by little, taking my time, and allowing the suboptimal nature of my environment to concentrate my mind on reducing, and it really does feel good.
When you love everything you have, and it all fits, and it is all high quality, and it all suits your climate and your lifestyle, the only option I can see, apart from reanalysing your style and finding whole categories of stuff to get rid of in a single sweep (like my lightweight silk dresses), is to ask yourself which is the best item in each category (where a given category is one that makes sense to you personally, not necessarily what someone else would consider a category), or which might not be the perfect 10 you thought they were, or which items you would be most sorry to have lost in a fire or something. Just ask yourself, for each item you are unsure about, whether this item is so important to you that it is worth the amount of space it will be taking up in your new place.
Best of luck!
Sarah
P.S. I speak as one whose style is not amenable to the standard 'capsule wardrobe' approach, which I would find very dull. It would be so much easier if a simple 'mix and match' capsule wardrobe of tops and bottoms would appeal to me but I have an aversion to that idea. My style honing has in no way taken me in that direction. To the extent that I can be considered to have a capsule wardrobe, it is one of outfits rather than mix-and-match tops and bottoms.