I took Billie and Katie's 2007 Canada Salsa Congress Lift workshop and am working up portions of that workshop for upcoming shows. I picked up a partner there as Billie carefully matched people without partners at the beginning of the workshop - no problems as she was an ex-cheerleader and was strong. They do *not* rotate partners in their lifts class - it's a trust and safety issue as a lift is 'lead and follow' taken to the extreme. And paired the couples together so one couple 'spotted' while the other worked with the lift or trick.
I also took their Spring 2008 Toronto workshop with my partner and we use three of those lifts and tricks in our current routine - as well as a lot of other drops and dips. They are very methodical and safe instructors.
I do advise the followers to spend some time strengthing their core muscles. While one is learning a given lift, one is having to maintain the position much longer than one would in a performance or a competition. Strength is needed, otherwise, the leader wil not be able to hold the follower in position or execute the lift. Leaders need strong arms, shoulders and upper back muscles too. Remember that one is working against gravity with full body weight.
Get the crunches and 'planks' and push-ups going fast!