Haven't changed my base fees yet, I might give it a try. Also good idea to open channels in between all the custodial wallets, but, why wouldn't they just open up to themselves? I'll need to investigate more this weekend!
Discussion
Not sure, have not check them in details. I think they have some channels between them but still they possibly charge a bit between each other. Logically, node operator like us can possibly target them to bridge liquidity between their channel.
Good luck with your experiment, hopefully you can get some profit 🙂