I have the 1755 sterilite tub rack from the Boaphile. It is a sideways rack. The tubs are 27qt. It uses belly heat though - not quite sure if yours does. You mentioned the heat tape running along the side - what did you mean by this? Is your rack heated by back heat? Just curious...

Either way, it should be perfectly fine. I use a VE200 t-stat with my rack and the temp is set at 88. My hotspot is 88 and my ambient is 78. The room temp is about 72. This setup works well for my baby boas (who like slightly cooler temps than BPs). And I use disposable cage liners as substrate and its perfect.

No reason why a sideways rack can't be a good permanent setup. It does depend on the snake - make sure your snake has plenty of room as it'll have a slightly shorter distance for thermoregulation. I think you just need to take particular care with adjusting the temps, but you should do that anyhow, lol!