This is my first time on the forums so forgive me if this is not in the right place. I have an old spruce bonsai that has been neglected for over 10 years since I collected it. I had a chronic illness that made taking care of anything very difficult. Now I have moved, am better, and need to help this tree recover and really shape it. It has had over 1/3 dieback over the last year from poor wintering and watering, that I am regrowing with kinetin spray (I know some plant biology), and needs to be repotted in the spring (or fall?). I have no idea where to source a bonsai pot large enough for it, the commercial bonsai soils seems not to hold enough moisture (summer dieback till I put in near constant drip irrigation), and since the tap is deep I don't know how to remove such a large tap without bleeding it to death. I have powerful rooting hormones and know how to use them, but thats it. I'm out of my league and need whatever advice I can get.

Very nice tree, wonderful deadwood, the foliage is leggy and should be pruned to produce back-budding.
Don't worry about bonsai pots and soil right now; first get the tree to a healthy state before doing any work on it.
You can lightly fertilise from now on till the beginning of the Winter, water it properly, and the vase looks big enough to keep the roots happy.
When it gets strong, and if the timing is right (beginning of the Spring, for instance), then you can repot it.
If you cut the taproot but keep the fine hair roots, it will not "bleed to death"; and root hormones for existing roots does nothing to help.

Interesting material. Seems this can become a very nice bonsai. It is going to require some advanced skills though. Are there bonsai clubs in your area?