Hi Bob,
You're right, there are a couple more places available on both...but at the moment the numbers are as follows:
Main tour only: 11 confirmed travellers 6 men/5 women ages mid-30s to mid-70s
Main tour with add-on: 4 confirmed travellers, 1 man, 3 women ages early-30s to late-70s
Kindest regards,
Julia