With reference, again, to BC's Electoral Map and the Regional District Map, this and the next (last) installment are the simplest at the Regional District end of things, more complicated when it comes to the ridings.
The Central Okanagan Regional district is largely "Metro Kelowna" and the immediate countryside. It boasts a population of just under 180,000 and because it only sends 3 members to the legislature, it would be significantly under-represented, except that Paradise Valley, which contains the Coquihalla 97C highway on its way out of the Okanagan, and everything south of it is part of the Penticton riding. So to make the math reflect reality a bit more closely, I'm going to lump Okanagan-Similkameen and Central Okanagan together to counter the resulting distortion. If I had location-by-location census data, I could do it that way but this is for a charcoal sketch, not a pixel-true, crystalline, exact image, so the "lumping" approach should be adequate for the purpose.
Central Okanagan's 180,000 or so plus people plus the 80,700 from Okanagan-Similkameen makes about 260,700
Central Okanagan's three ridings (Kelowna-Lake Country, Kelowna West and Kelowna-Mission) plus Okanagan-Similkameen's two (Penticton and Boundary-Similkameen) make 5
So, at 52,100 or so population per member of the legislature, there's some under-representation here, but not by the greatest disparity (see Metro-Vancouver).
I don't believe that Regionalized Proportionality should come into play where there is a collection of fewer than four seats. I don't have extensive research to back that up but call it a hunch. As I've been drawing this project to one conclusion, I've conceived of a follow-up that shouldn't be too hard to execute after the provincial election that's happening this spring. Ignoring for the moment the importance of local personalities in the urban areas and the clamor that may or may not erupt about strategic votes (voting for your least unfavourite candidate to prevent a REALLY bad option from winning), I'm going to consolidate several sets of ridings' electoral result to demonstrate, again just as a rough sketch, of how Regionalized Proportionality would have changed the outcome of this spring's election, just as an example.
And this is the place where I'll do the first consolidation. Although it breaches one of my principles (following Regional District Lines), it will honour the similar character of the whole Okanagan district with, I hope, not too sprawling a definition. I propose an "Okanagan" seat comprised of the new Penticton, Kelowna-Lake Country, Kelowna-Mission and Kelowna West ridings. It would send four members proportionally selected to the legislature in Victoria. I think I will also do a comparison that adds Vernon-Monashee to the mix, but I suspect that this will be an agglomeration too far.
My second consolidation almost perfectly follows the Capital Regional District as a single riding, except where some parts of Saanich North and the Islands may be in the Cowichan Valley Regional District. Here I propose a "Victoria" seat comprising the new Langford-Juan de Fuca, Esquimalt-Metchosin, Victoria-Beacon Hill, Victoria-Swan Lake, Oak Bay-Gordon Head, Saanich South and Saanich North and the Islands. It would send seven members to the Legislature, representing 51,400 people per member, so under-represented by about 2% (see the first post in this series for that calculation -- including my follow-on comment).