Bah, for Caelum I always take the Wizard's Tower: The higher admin score helps to prevent starvation of the hungry caelians and mammoths of adjacent armies and the high supply bonus is useful to last the 1-2 turns of the siege until nearby fliers arrive to relieve the sieged tower - and thanks to high admin the amassed troops dont starve after they successfully defeated the attackers. Sure, food becomes a nuisance in mid-game, but surviving until mid games is Caelum's main problem, for mage nations can only grow stronger as the game progresses (more research done means more powerful mages).
Furthermore I go for cheap pretenders in order to get good scales: order+3,growth+3,magic+3. Growth again helps against starvation and in combination with the Order Scale gives you enough money to pay all those expensive mages (yes, I do know that Caelian Mages are the cheapest around). In order to make the most of those expensive scales I recommend a high dominion strength (8-9). As written in previous posts: The actual dominon strength (height of the white candle) determines the chances for each scale to tip one step into the directon you have choosen at your pretender design so expensive scales with a weak strength might not pay off as well...
For the chassis, try a Fountain of Blood with some Blood and Earth magic in order to forge DwarvenHammers, EarthBoots+BloodStones for Staffs of ElementalMastery and in order to summon IceDevils and others of their ilk. Caelum does not need a pretender for manual site searching nor for fighting, but merely to bring in the magic paths that the seraphs lack... However, this is just my design for caelum which was pretty successful for me in a couple of MP games so far, but sure some people here will disagree!
However, that is the beauty of the game: The most important thing is to understand the design and the strength and weaknesses of the nation you're playing and while I might play Caelum, I cannot give you any advice on how to play Pangaea, because I lack the comprehension of the concept of Pangaea. Yet this certainly one of the reasons that keeps the game interesting even after a year of constant play...
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And back on topic, the initial dominion strength times 10 is the percentage chance for each temple to increase a candle (dominion) by one step throughout the entire game...