RNC modularisation redux

I have a similar problem to Sean McGrath as described in
http://relaxng.org/pipermail/relaxng-user/2004-July/000544.html and also Adrian
Robert in
http://lists.oasis-open.org/archives/relax-ng-comment/200407/msg00005.html but
there was no follow up to Sean's last email and there was only the one answer to
Adrian's. Given that it seems to work as required in my (limited) testing, is
specifying 'combine="choice" for every <define> in the base schemas (as
suggested in
http://lists.oasis-open.org/archives/relax-ng-comment/200407/msg00007.html) the
best way to go?

Robert