Congratulations on your new accomplishment!
I too am looking at my delegations and scaling back. I am going to focus on STEEM and one or two SCOT tribes (steemleo)!
I am however going to continue steadily putting in my own money to increase my stake.
You are correct though that picking a tribe that is a successful investment is a bit tricky. Also some tribes may be quite successful from the standpoint of community, but not from the standpoint of investment.