There are ways to review already burned items, such as the Item Inspector and the Self-Study Quiz - OR using KameSame. So, it’s strictly not necessary to unburn any items to go through them and rebuild your connection to them.
For this challenge, I would probably have used WK for the unburned items, while using KameSame OR the Item Inspector for the burned items, with the main focus being on the unburned items, and occasional work on burned items as a side-quest.
I’m currently doing the latter, just to keep those items alive in my memory since anything that I haven’t encountered yet in the wild will have a shaky foundation for long-term retention.
My own subscription will run out in a couple of months as well. 
I hope to get to around 80% burned items at which point I’ll consider WK done and over with. There is increasingly less point to use SRS after you reach 80-85% burned items. The reason being you’re increasingly facing leeches, which need a different approach than just SRS (or they wouldn’t be leeches).
In other words: you need other forms of input from SRS to build that real deep-rooted memorization. I find that only immersion do that.
So I would probably do what you’re doing - using WK for the SRS along with scripts like the Item Inspector - but shift more energy to just reading, listening, and watching stuff with no subs. Something that gives you a better sense of context for each item, so they stay in your memory for the long run.
I wish you good luck on your mountain climbing adventure! 
^>^ You can do it! 
. You basically have 3/4 of the whole WK in your review pile.
.