Okay so you have 5 x .5 mg tabs left. How do you feel on the .5mg?
You have done a very fast taper, and switched form xanax so I imagine that your system is pretty unstable at the moment?
I was in a similar way to you, on high doses of K and did a cold turkey for 8 days and just reinstated on V so it can be done, although my experience may not be yours.
Is there any chance at all you can get some more K to do a proper cross over?
If not you can try over the next five days to just subsitute the way I said in the schedule but shorten to 2nd daily instead of weekly and see how you go.
So tomorrow and the next day for instance, only take 3/4 tab of K. (.375mg) and 1.1/4 tab of V (2.5mg)
then the next two days 1/2 tab of K and 2.1/2 tab of V (.25mg K and 5 mg V)
then the next day two days 1/4 tab of K and 3.3/4 tab of V (125mg K and 7.5 mg V)
then finally onto 10 mg V. (5 tabs)
How does that sound?
Although I do think the very best for you is to get some more K, but if you absolutely cannot then you just have to make the best of what you have. But you will still have the problem of needing more V to taper with properly, unless you want to do an abnormally fast taper from the V too?