Hi Dan.
The Star Circle Pac has the same rules as a RTW - travel must begin and end in the same country. [Of course there is nothing to stop you ticketing Canada-Taiwan or whatever and not using the last segment, but that's another matter!]

The basics for the *CircPac are :

Valid on SQ TG AC NZ OZ UA NH RG only. (Long list of excluded code flights).

a) - 2 levels available. CP1 at 22,000 mls max and CP2 at 26,000 mls max. Fares available for Y J and F.

b) - It's not a "true" CirclePac (where travel is limited to Pac Rim cities) and does allow you scope within SE Asia and the Far East for routings, but only YVR SEA SFO LAX SAN and HNL are permitted stops in Nth Am. [See permitted countries further down.]

c) - Travel must include 1 (and only 1) Nth Pac crossing and 1 (and only 1) Sth Pac crossing. Travel must route via Nth Am and/or Aust/N.Z. Only 1 crossing between Asia and Sth West Pac permitted.
(i.e. - Asia/S.E. Asia/Far East to Aus/N.Z./Sth Pac islands such as Fiji etc).

d) - No more than 28 segments (inlcuding ground). Travel *must* start and end in same country and cannot transit start point. Only 1 intnatl dep and 1 intnatl arrival in country of origin.
Ground segments counted in mileage.

e) - 7 days minimum, 6 mths maximum stay. Min of 3 stopovers required, except if departure country is in Sth West Pac then only 2 stopovers is minimum. Max of one stopover (24 hrs +) per city, included in the three permitted transfers per city.
No maximum stopovers - limited only by mileage, routing and number of segment restrictions.

f) - Classes booked (pending carrier) are:
Y cabin - H B or M
J cabin - C or D
F cabin - A

g) - Changes to other than up to the outbound 1st international leg can be made after ticketing at FOC for a reval only, or USD75 for a reissue. No charge if cancelled before ticketing, but 10% of fare paid as cancellation penalty after ticketing if no flights used. After departure, difference (if any) between fare paid and the applicable fare for the journey already travelled. [i.e. full published one way Y J or F fare, so forgeddaboutit !!!!]

Countries permitted to be used in the fare:
AUS / Brunei / CAN / China / Cambodia / Cook Islands / Fiji / HKG / Indonesia / Japan / Korea / Laos / Malaysia / Myanmar / New Caledonia / N.Z. / Philippines / Western Samoa / SIN / Tahiti / Taiwan / Thailand / Tonga / USA / Vietnam.

I've only got the ex AU fares with me, but it may give some idea.
CP1 (22,000 mls)
F - AUD8489 J - AUD6269 Y - AUD2839
CP2 (26,000 mls)
F - AUD10,189 J - AUD7529 Y - AUD3409
They're the published levels.

Only the basics, but it should help you get started. Cheers.