I own VI. Booking is a year in advance with a non-refundable $20 registration fee. You can also add insurance that allows you to cancel up to the business day before the trip vs the normal 30 day cancellation.
Pinnacle tends to be less used. Right now, there are units available for most of the rest of March and all of April. There are 3 types of units; all studios. The smallest has 1 bed, then there's one with a single sofa sleeper and another with a larger sofa sleeper. The latter go first and cost quite a bit more. You don't have to book a week; any amount of days is fine.
Shuswap only has a few units; a mix of 1, 2 and 3 BR unit Nov-April only. You can book 3,4 or 7 nights starting on Sat or Wed; these are essentially weeks that they bought.
I like VI a lot, but they have fewer resorts. They do have an internal exchange program where owners trade in a week in another resort for VI points. There are usually quite a few options, especially in the SW US but there are also a few CA; mostly eastern with a few Whistler thrown in.
The resorts are nice; nothing fancy but kept in good repair and updated. It's owner run without the heavy sales presence; there is some, but 'no' actually is taken at face value without the need for arguments.