I made a simple chart to guide how I could use the overlaps:

////////////////////////////////////////////////
//////////////////////Hello/////////////////////
////////////////////////////////////////////////
/////+------------------------------------+/////
/////|(04)ABCDEFGHIJKLMNOPQRSTUVWXYZabcdef|/////
/////|(08)A B C D E F G H I J K L M N O P |/////
/////|(12)A65B  C50D  E  F40G  H  I  J  K?|/////
/////|(16)A   B   C   D   E   F   G   H   |/////
/////|(20)A    B    C    D    E    F    G?|/////
/////|(24)A70707B     C     D     E     F?|/////
/////|(28)A      B      C303030D      E???|/////
/////|(32)A       B0000000C       D2020202|/////
/////+------------------------------------+/////
////////////////////////////////////////////////
////////////////////////////////////////////////
////////////////////////////////////////////////

Where each space going horizontally represents 4 units of waveform entry. The N106 takes waveforms divisible by 4, down to 32 units long, shown vertically. Each letter represents a new bank where A = 0, B = 1, C = 2, etc.) Below, is where the channels would be set:

////////////////////////////////////////////////
//////////////////////Hello/////////////////////
////////////////////////////////////////////////
/////+------------------------------------+/////
/////|(04)ABCDEFGHIJKLMNOPQRSTUVWXYZabcdef|/////
/////|(08)A B C D E F G H I J K L M N O P |/////
/////|(12)ATTB  CPPD  E  FQRG  H  I  J  K?|/////
/////|(16)A   B   C   D   E   F   G   H   |/////
/////|(20)A    B    C    D    E    F    G?|/////
/////|(24)AUUUUUB     C     D     E     F?|/////
/////|(28)A      B      CSSSSSSD      E???|/////
/////|(32)A       BVWVWVWVC       DVWaltVW|/////
/////+------------------------------------+/////
////////////////////////////////////////////////
////////////////////////////////////////////////
////////////////////////////////////////////////

(copypasta)

In other words, call upper channels with little empty (straitline, silent, zero'd out, etc.) waveform patterns, then lower in the mml source (but simultaneous during playback) set a part with a busy larger waveform sharing the same bank space, and the upper channels will have sound!

In other OTHER words, Farler's Ultimate PPMCK ref had a lovely bank chart that explained the few years of tearing my hair out whenever I'd write something with a simple instrument change causing a seemingly unrelated channel playing a bass line to freak out or drop out entirely.

3:30 PM 9/12/2010 - ionustron