Alot of the venues in Scotland run on slippy floor, either polished wood, the green plastic gym type flooring or where i race its more like linolium. Schumacher yellow mini pins work really well on all of these surfaces, 21mm all round with foam inserts if your wanting the most grip/performance but they do wear out quite quickly. Wear rate really depends on the track surface, someplaces its 2/3 weeks (our venue) others its 6 weeks plus. At our club we all use the 25mm yellows now as a control tyre as they arent that much slower overall and they last for up to 8 weeks depending on how heavy your thumb/finger is. Hope that helps