Whiteboard markers

I am finding that I have to teach in rooms with only low-contrast boards including visualizers and dry wipe marker boards. My lecture theatre has quite a large white dry wipe board but we only seem to have white board pens which make a line about 2 or 3 mm wide, which is invisible to much of the audience even in the best lighting conditions. A quick google indicates that dry wipe marker pens are available up to 5mm.

Does anyone have experience of using these pens? In particular

  1. are the lines big enough to be visible in a large lecture theatre
  2.  Do they last a lecture
  3. Are the alcohol fumes from them a problem?

There are some reviews on Amazon but they do vary by make from one to
four stars.

Also has anyone seen bigger than 5mm ?