Recently my mind turned to off board artillery markers. Up until very recently I've been using 15mm stuff that has been placed, on- table, on pieces of red card to mark its off board status. It works well enough except for three things. Firstly, most heavy artillery is not available in 15mm (and why should it be as it will seldom, if ever, get used on-table). Secondly it has a large footprint and takes up too much room. Thirdly, even if it were available, it would take an excessive amount of time and money for its gaming value - cost benefit.
I was thinking of using pictures mounted on thickish card and so forth, then I suddenly remembered previous forays into WW2 in 10mm and 1:300 scale. A light went on.
I googled Heroics and Ros. http://www.heroicsandros.co.uk/heroics/pdf/webcat.pdf
Immediately thereafter ordered the guns I needed - some of which are pictured above alongside my 15mm stuff. Their range is not universal, but it has a good deal of the more common heavy stuff. It is also very cheap - £0.40 a gun and crew - and Andy Kirk is a pleasure to deal with.
I decided to paint and base them purely as markers - which took out lots of work - and I think they fit the bill perfectly. It will not be a new idea, but I think it is a good one and worth repeating. A very small corner of the field will be forever off-table.