Thanks for your awesome feedback! Defining exact hex color value, entering exact thickness/opacity/text size value is now available in Xodo beta! See http://feedback.xodo.com/knowledgebase/articles/1119511-change-style-of-an-annotation-color-thickness-o.
To enter exact color HEX value, see: http://feedback.xodo.com/knowledgebase/articles/1849546-annotation-color-picker.
To define and select style presets, see: http://feedback.xodo.com/knowledgebase/articles/1851553-setting-an-annotation-style-preset
You can become our beta tester as described here: http://feedback.xodo.com/knowledgebase/articles/829551-becoming-a-beta-tester.
Just FYI, “more”/“plus” button for adding customized tools to toolbar is under review! Hopefully we can implement it in the future!
Xodo TeamFilippo Alberto Edoardo Nuccio commented
I second this! When I annotate my pdf I basically only use pen, pencil and marker. I would like to be able to have these buttons as first, not hided below with the others which I never use. It would also be great to customize what I can have, like two pens instead of one (so I can fast access red/blue ones without hitting and waiting).