I really do not beta test much anymore (well except for the open WIP betas) for the reason I work better with a little feedback, this way you can work in tandem with author know what they are focusing on, and it makes it easier for me to notice other things while doing the normal low-high feedback.
One of the best authors I had the privileged to work with with was @Lucid he welcomes feedback and you can see the immediate responses in his work and comments. One that I more thank liked mucked up is Sergi’s and prolly made poor @jasonstevanhill pull out his hair and to beat me like a red-headed step-child. So I would suggest viewing this forum first for all prospective beta testers:
also
Look at the requirements for high and low level feedback this is what will be required of you, mid level is the what editors like @Fiogan get hired for, so know what you are getting into before you say pick me pick me! Also know being a beta tester for CoG is a privilege and a job your input makes all these games better. We all have seen a game or two in release that was buggy as all get go, that fault lies with the beta testers, bugs can not get squashed without being reported.