Get the combination A/D set by the best maker you can afford for maximum versatility. Hamish Moore seems to be the bench mark in SSP and Border Pipes. If you want more volume in sessions then either play with another SSP piper or look at Border Pipes. Playing in D does help cut through in a session but in my opinion you do loose the best and most distinctive part of an SSP`s sound if you move away from A. Examples of SSP`s have been around for centuries but like all modern instruments, they have been adapted to suite modern standard tunings and materials. The only difference with SSP`s is that this hasnt been the gradual process as with other instruments which have "evolved" over time. SSP`s were virtually extinct and had remained largly undeveloped until 30 years or so ago when pipe makers like Hamish Moore started to adapt and improve the instrument for modern demands and playing conditions based on the developements with other types of pipes over the last 100 years or so. However the instrument is still very traditional in feel with most instruments having few if any "keys" and a very limited range.