Titanium struts are the best choice there is I think. The trick is that you most probably need to have struts with thicker wire compared to steel struts. Titanium is a far lighter material and doesn't need to be straightened even after a bit rough landing if the length compared to thickness is correct and you have the spring loop correctly designed. I use the Central Hobbies 3/16" titanium struts on my Typhoon 2+2 (4,9kg) and the struts work perfectly even on grass field.