How much do you trust the Collection class?

[DEXWERX]

Contiguous blocks of 88 (&h58) bytes each.

Actually, this brings up yet another question. From what you've (DEX) posted, we only know about &h1C bytes in the VBCOLLECTIONITEM structure. Where/what are the other 60 (&h3C) bytes?

This isn't DOS, and I know enough about memory management to know I can't make any deductions about this. For all I know they are more slots in each bucket. CS101 says a bucket usually consists of multiple slots (2-3 according to Wikipedia) - to make collision resolution easier.