Extensible spin habitats in GURPS Spaceships

[Proteus]

I'm toying for the first time with the GURPS Spaceships rules, for a semi-hard TL 9 setting that lacks artificial gravity.

I see the rules on p. 30 for "Spin Gravity," based on the SM (and thus the radius) of the vessel. What I don't see are rules for the sort of designs where habitats can be extended or retracted (or, in extreme cases, reeled and unreeled) to produce effective radii far larger than the craft's normal one.

Perhaps, if a habitat occupies double space (and double cost, not including specialized rooms), it could be extended to provide spin gravity as if the ship were the next SM larger. So, for example, a SM+10 exploration ship which payed double (space and cost) for its crew quarters could extend them outward to produce 0.3G when spinning (as for SM+11) rather than 0.2G (as for its actual SM+10). I know hull spaces generally go up by threes, but this seems a much more limited use than one would get from the usual scaling process.

So, does that sound more or less fair?

Follow-up question: what if the naval architect wants an even further separation? Some real-world designs have included cables to achieve large separations for spin. Would it be appropriate to continue doubling (so our SM+10 ship needs the equivalent of four spaces for the habitats to spin for 0.5G, emulating SM+12)? Or might it be better merely to charge one additional hull space per extension (so that those four spaces would now let our SM+10 ship's single habitat emulate SM+14, or a full 1G)?

Which of those options sounds more reasonable to the assembled GURPS gurus?

Whichever the solution, I'm guessing that each extension would impose an additional -2 on Handling while in use, above and beyond the -2 assessed purely for having spin gravity in the first place.

Having not yet messed with the space-combat rules, I don't know how long the actual extension or retraction process should take -- but I'm pretty sure it should be decided ahead of time, since it's bound to come up. Help would be appreciated there, too, in coming up with a reasonable and balanced answer.