I'm not experienced enough to give proper advice, but I will say that waiting for the growth to be 6-8 inches tall seems excessive, no? Where is the plant going to get all the nutrients for that new tissue with such a small amount left in that withered backbulb? Is there really enough in there?

It's more a case of waiting for roots 3"-4"/7.5-10cm long before watering than the size of the shoot.

Ouch, there isn't much energy in that bulb so you probably won't get much more than an inch or so of roots before it runs out of gas and dies.

This is what I would do. Drop the pot in some water so that the spag absorbs water from the bottom. Once the spag is soaked through, pull it out and let it dry in a warm spot with decent light. The new roots are still short enough that they shouldn't be negatively affected by wet spag since they don't appear to touch. The moisture absorbed by the old roots (if they still function) should provide enough energy for another month of root growth. If you do this, can you post pics a few days after the soak? I'm curious to see how much (if any) the back bulb aborbs.

I'll try this tonight and report back

I would also put it in a much smaller pot with fresh mix, taking care to not damage those root tips.

Remember, that's just the beginning of new growth... it's not going to stay tiny. I'd leave it in the existing pot, Once the growth matures, it is may very well become bigger than the old psedobulb. Catasetinae, after all, reinvent themselves every year, And I wouldn't worry about "overpotting" ... once it gets going, I'm not sure that it is possible to overwater one of these. It's hard to keep them wet enough once in active growth.

I don't want to chance hurting any of the old roots that may soak up water. I think it's best to just let it be in this pot for now.

I took a couple pics last night before soaking. I will check in a couple days to see if it fattens up any. I have brought it to work as the temps are kept a few degrees warmer than my house, especially at night.

Cool! I'm curious to see what it looks like on Monday!

Me too. I figured leaving it on my desk I won't look at it all weekend either. So, fingers crossed, I will easily see if it works.