No, just trying to play with BTH (in a different wallet, in a VM on a different machine). My understanding is that I should transfer my existing BTC to a new address before importing the private key to the BTH wallet.
Not sure how I should proceed here.
Ah, then yes - moving it first is good advice - Don't risk ~$28k for the sake of ~$500.
That said, Goatpig is working on a BTG signer for Armory, but no ETA or any promises there. If you're willing to sit tight you could wait for that and you won't expose your private keys.
If not, then you'll need to send to your new wallet. Get it setup to receive at a P2SH-P2WPKH (segwit) address, then figure out what fee you're willing to pay/how long you're willing to wait for the BTC tx to get confirmed.
Core 0.15 & the current RC of Armory have a smart estimation feature that might help you decide, but there are all sorts of
charts/
graphs online - I can definitely say you don't want to pay 2 BTC in transaction fees. Right now... somewhere in the region of 100-300 satoshi per byte possibly.
Edit:
All of this is still a lot of greek to me. I don't know what a "segwit" address is.
Segwit, also known as segregated witness, is a fancy name for an address format that basically makes transactions smaller, thus reducing transaction costs for you. Instead of addresses looking like
1blahblah, they look like
bc1blahblah or in Armory's case
3blahblah.
You don't have to use it, but unless you are in a rush it'd make sense to read up on it.
Edit2: Hang on, do you mean BTG (Bitcoin Gold) or BCH (Bitcoin Cash)? Just realised a one letter typo would get you to both.