Don't know if this is in common usage, but rather than use a bit of timber as a batten for tiling a better idea is to get a piece of 150x2400 melamine faced chipboard aka Contiboard, cut down the centre length ways. Hey presto two dimensionally stable perfectly straight battens with a nice wipe clean surface that tile adhesive tends not to stick to making them reusable.
When it comes to attaching them to the wall use screws and drill/plug the wall as necessary. However if you drill a couple of 10mm holes next to each other and join then up (or cut a slot with a router) and use penny/repair washers on the screws then you can easily adjust the battens to get them perfectly level by slacking the screws off a bit and nudging the batten up/down till the spirit level says it is true.
When it comes to attaching them to the wall use screws and drill/plug the wall as necessary. However if you drill a couple of 10mm holes next to each other and join then up (or cut a slot with a router) and use penny/repair washers on the screws then you can easily adjust the battens to get them perfectly level by slacking the screws off a bit and nudging the batten up/down till the spirit level says it is true.
