Thanks [USER][/USER]h ! Exactly the sort of advice I was looking for. I managed to accumulate 160k oil (to start my HT Mk6 upgrade while it is discounted) in 2 days with 2 training blessing sessions. Here's my cycle.
I keep my medals at just over 2K. As soon as my Victory Chest starts, I get the 12 stars as quickly as possible with a normal total-destruction army (6 tanks, 8 Field Mortars, 20 shooters, 3 healers, 6 footies, 5 supersonic fighters), and hope to get 15K oil. Then I kamikaze a base with at least 4K oil with just my barracks troops, rebuild with my raiding army (raiders and footies, a few shooters) and start a training blessing. As soon as I have about 10 raiders and 30 footies, I start raiding.
I look for bases with more than 3K oil and accessible oil wells. I hit one well to make sure they are full, then hit the rest. If the refinery is behind just one wall I might go after it, but it is rare. If I find a base with an exposed TC I will hit it with some footies to get the stars, just so I don't drop too many medals. I can hit about 30 bases in the hour, since I am not waiting for a complete army. I raid between 20K and 40K oil during the hour, depending how lucky I am.
After an hour I am down to about 1700 medals, and then I rebuild my regular army and start the climb back to 2K medals (after a nice long break; an hour raiding is pretty exhausting). I play for about 10 minutes at a time, once or twice per hour. I will make about 20K from those medal climbing attacks. So during an 18 hour cycle I will raid 50K to 60K in about 4 hours of play time. My wells generate about 25K per day. I rarely get raided; I'm level 253.