V28 Rack - Heat Tape Questions

I'm likely going to be ordering a rack for Vision V28 tubs (23" x 16" x 5.75") rack in the very near future. I have a few questions that I'm hoping you can help me with. Thanks in advance!

1) Is 3" heat tape sufficient? I ask because it is what API stocks and they could provide me with the exactly what I need for the rack I order from them.

2) If 3" is not sufficient, what size do you recommend for this size tub? This would mean I would provide the heat tape myself and have API do the routing needed on their end for me.

3) With an 11-high tub rack, would there be a temp difference from the bottom tub to the top tub to warrant separate thermostats?

4) If separate thermostats are NOT recommended, which tub do you recommend placing the probe under (bottom, middle, top, etc)?

5) If separate thermostats ARE recommended, which two tubs do you recommend placing the probes under (bottom and middle, middle and top, bottom and top, etc)?

Best regards,
Eric