Dow 111 High Temp rated lubricant that is FDA and NSF approved. It is food-safe and holds up well under the high temperatures of E61 groupheads. This is what you want to use if your lever on your E61 machine is either hard to move or squeaks when actuated.

A bottomless portafilter can help dial in the all the elements of pulling a great shot (grind, tamp, extraction time) by giving immediate feedback to the barista. Channeling of water caused by poor dosing and tamping can easily be spotted by little "spouts" erupting from the basket. Mottling or Tiger-Striping can easily be observed indicating a proper extraction.