Karl and his Microcasa a Leva. Jim and his Semiautomatica. Dave and the Roadshow tamper evaluations. Now this. Are single espressos the new "in" thing?
While I have no experience pulling singles, I can offer a suggestion on dealing with single-spout portafilters. Below is a "portafilter park" that I created for less than $0.50 (a PVC coupler from the plumbing aisle):
It works best for snub-nose spouts, not the long ones that came with your Anita. To eliminate clutter and make it easier to work in any environment, I've gotten away from such implements. Instead, I tamp on the countertop, pushing the "ledge" of the portafilter / spout against the countertop's edge. It's unnecessary for bottomless portafilters, or when tamping with the basket out. When it comes to double spouts, below is my favorite by La Marzocco:
A nice clean 90 degree angle and the spout ends are close together. It works for singles and doubles.