No brim needed.  Support is built into the STL file so no support needed either.  Cut the 2 supports after printing is over and file them down.

If it is too tight or too loose for your glass, boil some water in a tea cup and then dip the top into the water for 20 seconds and then bend to the desired tension while blowing on it to cool.

To add text, create STL file of text .1mm tall.  Print that single layer with bottom layer height set to .1mm in slicer.  Then swap filament and print the clip on top in a different contrasting color.  Make sure bottom layer of clip is .3mm giving you .2mm to .3mm of vertical space for the filament to flow around.

Creating 3D text in any font is especially easy in sketchup.  First draw a flat square 20mmX20mm then use "tools" "3D text" and give it .1mm z depth.  

Use STL exporter add-on to get STL from sketchup.  Export only the letter(s), not the 20X20mm square.

In cura make text bottom layer .1mm.  I usually found Cura worked best if I set nozzle to .4mm (truth) and shell to .3mm but then increased flow on printer to 133% (to compensate for .3mm wide lines).

I used font "Georgia" for larger letters and Arial for smaller.  Arial is good for small text as the line width is constant (G in photo above has variable thickness e.g. top is thinner, left side thicker).