Canadians with Interactive Brokers, can you answer these questions?

[SeaDub 2]

I've seen some answers in the forum that are applicable but not directly from a Canadian with Interactive Brokers who specifically answered these questions, so starting a new topic.

1) Do you hold your trading cash in CAD or did you exchange it to USD?
I understand I do not need to exchange it but can borrow USD to buy US securities, I will just pay interest if I hold a negative USD balance.

2) Is your IB base currency set to USD? This seems to be required to ensure DAS Trader shows the correct balance and buying power.
Mine currently shows the account balance equal to the CAD balance, I can see this causing problems with DAS assuming it's USD buying power when executing hotkeys.

3) Come tax time, do you switch your base currency back to CAD to run reports for taxes? Do you do it more often, say for monthly reports as well?