I did the same, buying the aggregates in the gradings which the local hardware store has, with the finest sand also being 0.1-0.3mm like yours. The only thing you might like to consider is some super fine quartz flour, fly ash, or alumina. All the academic articles I have read point to about a 30% increase in strength and rigidity if your aggregate is graded done into a fine powder. I got some Alumina from a pottery supplier. In making cement concrete they stop the grading at fine sand, because the portland cement is the fine powder. Since we don't have that, it makes sense to add a replacement. Using Thomas Zietz XLS, I ended up with 12% alumina in my mix.