dimensions are 16.5 wide and the tub is 4.25 tall. i crunched some quick numbers for ya:
16.5w x 6 tiers = 99inches or 8.25ft
+ 4.25t x 6 tiers = 25.5inches or 2.125ft
= 124.5inches or 10.375ft total of heat tape needed
i would just get 11 or 12feet just in case of clearance. u can always cut of extra. also looks like 4in wide heat tape is recommended for this rack.
Edit: also looks like the 4in heat tapes runs at 6watts/ft. u would be running 72watts for a 12ft strip. the VE-100 rated at 700watts would be fully capable of handling it. :gj: