Have a bit of experience taking cuts w these... they are my favorite starting cubes... stay very airy so no issues at all w DO or the like. Bene's even take well to it. Would rec pulling the finer felt from the starter cubes as my roots don't like to grow there & it stays much wetter. Just peal that stuff off is my vote.
About to try the insert on the Ebb&Gro, though traditionally coir myself. Problem had always been top feeding & the STG's do not distribute moisture well... tends to channel with single or dual point top feeds. Seems better suited for a flood&drain or all out top-fed by hand. Somewhat flimsy so will likely need additional support, e.g., pots.
Definitely more convenient, definitely. Ultimately will depend on final quality of meds, so...
Peace.