As to your second question. Listen to desired hd station by selecting the freq, pressing the "list" button, use the right rotary dial to select the sub channel. Then press and hold the button you wish to have as a preset for it
FS:Sub Amp - works w/ Technic harness! MRD-M300 - cheap
DON'T BUY FROM RAF555!!!! Promised fix! - strung me along til Paypal dispute period expired!