When spending from a cold storage wallet with multiple pre RingCT (and no post RingCT) outputs what are the best privacy practices?
Spending in this context means the eventual moving of these funds to a new cold storage address generated by Ledger Nano S when Monero support is available.
Another solution may be to use a new command sweep_single that I proposed recently (#2634). This allows you to spend each one of your pre-RingCT outputs individually, preventing inferences of real spent outputs in the rings through the time alignment.
I'd do a sweep_all with a bigger ringsize to merge them all in one RCT output, followed by a couple of sweep_all to yourself (AKA "churn") with default ringsize at random intervals.
You can send that first TX directly to your Ledger and then use the Ledger to do the churning TXes, as it will likely be more user friendly than "manually" with the cold wallet CLI where you have to pass around some files. Preferably hide your IP via Tor/VPN if you want to hide the metadata as well.
