Thanks for your reply. I have dropped my Y-splitting aspirations in favor of simplicity and saving space. Also, I've decided to use a Lian-Li PC-73SL instead of the G5 case, again to reduce hassle.
I've hosted the compressor manual here:
You need to look at the F-Series (tall). Hope that has what you need to know.
I'm thinking of removing the HD cage & 3.5 bay and putting the compressor there. I'm not sure about where the condenser will go, maybe above the PSU if there's room. Since I don't need to cool both the CPU and GPU, I'll probably stick with the 1/4 HP Compressor, as long as it gives me a negative idle temp. As I understand it, voltage and general mobo stability is the limiting factor in OCing on a phase change system, not heat.
I don't have all of the necessary tools but can start acquiring them as we move towards the summer months... I think I read somewhere that if you're smart you can do this for about $100.
Thanks for your reply, let's keep talking.