You've taken the first step to contacting other HyGrid artists by posting here, on the HyGrid Topic. Welcome! Hello!
As for Wurmhoels, the method to create them is kind of buried in the interface right now. Need to fix that. Essentially, reserve some pieces (or not) then go to ...rescon?m=wurm
Choose the "where" and "which" and then reserve that selection. You'll be given a confirmation and a link to use when uploading your "wurmhoel" piece.
For those who don't know, a Wurmhoel is a HyGrid piece that "bridges the gap" between two or more older HyGrid pieces. It acts as sort of a "dimensional pinch point", allowing disparate HyGrid squares to become part of the same neighborhood.