Nothing but Zbrush reads a .ztl … but …
Actually with Decimation Master you can share your work with damn near anyone now…and all for free
(you can also export out a .dxf and umm…some damn format for 3d printers…I don’t remember the extention though.)
Anyway, you can take a mesh and decimate it to under 1 million polygons. Then have them view it in anything that can look at a .obj.
xNormal is free and can take in 2million I think…not sure on that though (I do know it can handle a million.)
I’m not sure what Marmoset (8monkey Labs) can take in… also free, but I haven’t tried to push it yet.
Anyway, if I were you, I would send off a .obj of your object after decimating it, and a link to xNormal. have them install xnormal and then import that obj and go into the 3d viewer in the program.
Hope that helps