This is pretty close to what I routinely used to do in SAS/Graph when I wanted logarithmic axes. Specifically, I always ended up creating my own tick marks. But I have always found that using 1 2 5 and multiples of 10 of those numbers for the tick marks works well. In this graph, which has the odd offset and hence a zero, I would have tick marks at 0 1 2 5 10 20 50 100. The 1 is a little crowded and could be omitted but it's a very important value and therefore to me worth a tick mark. Specifically I would not have used 25 but rather 20.