As the topic.

 

Now I can only right-click then choose autocast, that's two click.

 

Is there any ways to one-click autocast?

Unfortunately, l believe the basic spellbook is the only one that allows you to left-cliick auto cast. The Ancient spellbook's spells have to be selected from the right-click menu.

And thank [bleep] for that. Once you become better at using advanced combat techniques, you'll realise how much of a pain left click autocasting is.

agreed, mage boxing with storm of armadyl is a nightmare due to left click autocast.