SOLUTION...
welp, thanks to the personal help of "prowebscape" off-forum, we got this figured out and working.
i’ll post this here in case anybody else in the future finds this thread useful...
first, i had some upper & lower case characters mismatched. i think if from the beginning i used all lowercase "tvcnd" and "GetField" accordingly, this might not have taken so long.
and here’s my configuration that we’re using now (thanks to prowebscape) that works!...
TEMPLATE "General" includes...
[+phx:if=`[* sidebarcustom*]`:is=``:then=`[*sidebarcustom*]`+]<br />
[+phx:if=`[*sidebardocument*]`:is=`yes`:then=`{{sidebarchunk}}`+]
(yes, that's a space after the first asterisk only)
TEMPLATE VARIABLE "sidebarcustom" is set to...
TEMPLATE VARIABLE "sidebardocument" is set to...
Input Type: CheckBox
Input Option Values: "yes==yes"
CHUNK "sidebarchunk" is...
[[GetField? &docid=`218` &field=`content`]]
and of course i’m using a document named "SideBar" which has a doc id # of 218 and a template of "blank" for the content.
and all this wouldn’t be possible without...
the GetField "snippet" downloaded from
http://modxcms.com/getField-667.html
and the PHx "plugin" downloaded from
http://modxcms.com/PHx-1006.html
welp, thanks again to all who contributed and i hope this helps someone else someday.
cherio,
-jason.