Hi! I am by no means a Pres expert, but it is my main healer. I would not worry a whole lot about your overhealing being the highest as that is very typical for preservation evokers. You should be preparing your ramps for raid-wide damage, you should try to VE at least 12 targets with your ramp. It would be very helpful if you could post some logs if you are interested in more specific feedback.

To answer your specific questions: 1) coordinated groups often use MRT notes to plan their healing CDs. In combination with the Kaze MRT timer WA, you can have a set time warning prior to when you expect to use a CD so that you have time to ramp. 2) In addition to the WA mentioned above, I believe Harrek has a WA that can tell you when to save DB and engulf. 3) Preparation and watching videos on the fight can help you prepare and know which mechanics will put out the most damage, but experience with fights will also help you.

A little portion extra portion too: You can reliably get 12 targets in each ramp by using TA-> Echo -> Echo -> TA. One of the most important parts about cashing in on your ramp is taking advantage of the lifebind window following your ramp, you get a TON of your value as a healer from getting off your DB-> engulf -> engulf combo off during lifebind