many thanks now my sleepy head can rest
Brigger,
For my Solo stem I use a 1/2" stainless steel medium to fine mesh screen.
1/2" = 12.7mm so I would imagine a 13mm SS screen would do you just fine.
I slightly dome the screen over the end of a Sharpie marking pen. Put the screen dome side up into the glass stem bowl and tamp slightly with the Sharpie to seat the screen. Turn on the Solo, load up the bowl, allow the Solo to heat up to your desired heat level (I start at 4), then insert the stem into the Solo. Wait about 30 seconds or so then have at it.