Revised Assumption

Having read and reviewed more about my desired listening levels, I have come to the conclusion that 100 dB with 6 dB of overhead is probably a little too much. I believe that a value of 90 dB at the listening position is more sensible. Therefore, my assumption would change from a required combined speaker and amp able to deliver around 96 dB at 1 W at 1 m. Given a small buffer, the target range should be 95 to 98 dB. Of course it would be nice to have additional headroom of say 6 to 9 dB, but given my basic premise, I believe that the revised SPL levels are more realistic.