Anyway, gluing the mini's to the coins leaves an unsightly - to me - 'lip' so, many moons ago, I started using DAS modelling clay to hide this. Originally I could only find it in my FLGS but recently, since the FLGS changed hands, I found that you can get it in Rymans the stationers.
|DAS modelling clay|
|15mm Plastic Soldier Co Russian and QRF Russian|
Then I take a piece of the clay and press it down onto the coin to hide the lip and smooth it out using a knife:
I find that this extra weight in the base gives the figure an added stability, as well as making it easier to stick magnetic sheet to the bottom. The figure in the above pic has also had the clay spread on top of the slotta-base to hide the slot and give a bit of texture.