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 Teamkrys commented
Love this idea. Have been using Xodo for almost a year now and it's been great. Would love to be able to switch easily between different coloured highlights (and other tools) through a customised side bar of sorts. It's a bit of a bother as is, especially when selecting different transparencies.
Regardless, thank you to the developers for all the hard work. It's an incredible app.