Right boob packing in at 12 days - what can I do?

[Phalarope]

This is DC2. I fed DC1 until she was 15 months, but at about 10 months she developed a clear preference for the left boob, and poor old righty slowed down a lot and I ended up with an impressively lopsided bosom.

DS is only 12 days old, but since yesterday my right breast is already soft like when breastfeeding is well established, and I can't feel the letdown as strongly on that side. He comes off the left pretty much swimming in milk, but not on the right, and sucks more slowly.

What can I do to get righty back on track? Mostly for vanity...I don't want a wonky bosom from the start! Am trying to start all feeds on that side -.will that help?

For info - DC2 had a tongue tie which was cut last Friday, but has piled on the weight regardless, so not sure that's the problem. His latch is still a bit shallow but we're working on it. The right breast has a flatter nipple but hasn't seemed to cause latching problems for either DC.