Interesting question. Not sure if it relates to visual-spatial but our DD is high in VS and performs much better in individual instruction for things like skiing, swimming, horse riding etc. She also loves math with her tutor one on one and flies through material. But yes, individual lesson are much more expensive so we save them for "when needed" to get the most value from them. In some areas the social aspect is as important as the activity so it just depends. Also some kids do learn well from watching what other learners are doing.
I wonder if all children get more return per hour of instruction if lessons are one on one. Depending on what the activity is, could you add a lesson or two of individual instruction for two reasons. You could try and gauge if there is any benefit and, additionally, you could get feedback from the instructor on how she is going and what realistic expectations are for her in that area.
