If the bearings go in without being pressed (ie: you do it by hand), take the frame back to the shop and have them order the correct - oversized - bearings. This is mainly a problem with the older Madones, and the issue seems to have been cleared up. However, the bearings do need to be pressed in (you can make your own press, BTW, it isn't hard, and shouldn't cost more than $3, even in Canada).
The BB90 standard is a Shimano compatible standard. You need no adapters, the bearings are 24mm on both sides, and they aren't specific to one side or the other (you can put them in on either side, in either direction).
One piece of advice: if you plan on riding in the rain, or have bottles that sweat, you will want to head to a marine supply store buy MARINE GREASE. The reason for this is that the design of the BB will actually cause water to channel into the bearings. Even though Enduro does a good job of packing the bearings with grease, the grease isn't very water resistant, and will eventually wash off. Repacking is very easy. Using a very small screwdriver or pick, pry the bearing cover off and flush out the factory grease (I like to use WD-40 for this). Let the bearings sit for a couple of hours, to let the degreaser evaporate. Once that is done, you can put a small amount of grease on your palm, and push the bearing onto the grease, so it coats the inside of the bearing (you can YouTube "packing hub bearings" for an example of what I'm talking about). Once the bearings are nice and greased, replace the seals. It's a little messy, but works wonders to extend the life of the bearings.
2013 Madone 5
2012 SpeedConcept 7