Using koji to build against dist-5E-epel-testing?

[Ray Van Dolson <rayvd bludgeon org>]

Can anyone give me some pointers on using koji to build against
packages in epel-testing?

Tried using a target of dist-5E-epel-testing-candidate but it's still
using the most recent "stable" package.  If I do a koji latest-pkg
dist-5E-epel-testing <pkg> I see the version of the package in
epel-testing I want to build against, but no idea how to specify a
"tag" in my koji build command...

Need stronger fu... please help :)