Here's the parts of the SPC routines I modified. I labeled them to make it easier to remember what they did.
$C7/01EA BF 11 0E C7 LDA $C70E11,x[$C7:0E11] Loads the instrument table
$C7/0304 BF 0F 0E C7 LDA $C70E0F,x[$C7:0E0F] Loads the middle of the last SPC pointer
$C7/050F BF 18 0D C7 LDA $C70D18,x[$C7:0D18] Loads the SPC pointer table
$C7/0515 BF 19 0D C7 LDA $C70D19,x[$C7:0D19] Loads the second byte in the SPC pointer table
$C7/051B BF 1A 0D C7 LDA $C70D1A,x[$C7:0D1A] Loads the third byte in the pointer table
2008 Edit-Currently, I think I may have been wrong about C70304. I haven't seen it it executed. So it might not need to be changed.