but then u can't send btc to that 2nd wallet from the 1st wallet on the same computer.
my goal is to save the majority of my btc on a flash drive in my safe and not have to pull it out for several months. then i'd have a 2nd wallet with spending money on my computer. should i just send the btc to a client on another computer? is the wallet.dat file interchangeable btwn mac and pc clients?
just use multiple accounts to send between them, each user have wallet created in different place
flash drive is not good idea, if it fails there is small chance of recovery of wallet, backup on 3-4 different mediums and two locations is minimum that you have to do to be safe
personally i have backup of savings wallet on three separate disks in my pc (all with full disk encryption) and copy on external drive and attachment on email account
after i found out that my bitcoins are worth over 6k usd i added dvd-ram, microsd card and base64 copy printed on laser printer on another location
all of course with heavy encryption

i know it is a bit paranoid, but different medium, different location is a must have for long term backup
A printed copy isn't a bad idea either... I mean, heck, you can always OCR it back in, and convert it from whatever base you put it in. And if the OCR fails, you could hand-type it all. It'd probably be worth whatever is in your wallet at that point...
Just in case all your electronic media fails.