Could it be this?
I haven't gotten the March/April issue, so no clue on exactly what you're referring to, but am hoping you're talking about something on the order of :
http://www.geargrams.com/
Pretty nice little site to help figure out how much weight you're dragging around, great planning aid (coming from someone who notoriously packs the kitchen sink, just in case...sigh.
Alternatively, I think you can take a look at that issue, and other previous issues now on site.
Hope this helps ~!!