The Timberline Chain Sharpener (http://www.timberlinesharpener.com/) sharpens at a 30 degree angle unless you use the accessory angle guides which are supplied separately and provide the ability to sharpen at 25 and 35 degrees.
I use Oregon 22LPX chain on my Stihl MS260 which has a recommended sharpening angle of 25 degrees.
I queried the availability of the additional angle guides for the Timberline with Radmore & Tucker (http://www.radmoretucker.co.uk/) this morning but was advised they don't stock it and it would perhaps be a special import from the USA if I wanted one. They also stated that they've sold around 60 of these so far, many to people who will be using them at 30 degrees on chains that will be specified for 25 degrees.
So, I've a few thoughts/questions. How important is that angle? Are those five degrees enough to make a noticeable difference to the characteristics or handling? Am I likely to notice a difference if I sharpen my Oregon 22LPX to 30 degrees instead of 25? Should it matter, I'm mostly felling oak, beech and ash at the present time.
It also got me wondering how/why you'd choose a particular chain. I didn't really have any input into mine! I ordered the Stihl MS260, asked for a spare chain and got the Oregon 22LPX which seems to do me very well.
What chains do others use?