Hotspring Spa Classic E drywell leak

[bjmsam]

My Hotspring Spa Classic E manufactured during the 1987 – 1988 production year works well but recently began leaking past the thermostat capillary bulb tubes that emerge from the drywell (not past the O-ring gasket that seals the drywell to the tub). I managed to stop the leak with silicone but wish to pursue a proper repair. Questions:

1. Must the drywell be removed to determine whether it is the short or long version?
2. Does it matter?  Only the long version is available!
3. In case sourcing a replacement proves problematic, is it feasible to repair a copper drywell?
4. Can the drywell be removed and replaced without draining the tub?

TIA!