I tested this a while back, and it did upload more than it downloaded per day. But it will take a long time to "make up" for the 450 GB it has to download first.
I wouldn't run a laptop just for this. It's not worth the electricity, and considering it has a small disk, it's probably low on RAM too.
Old laptops are good for running untrusted wallets though, that's what I do:
I've added this to my toolbox for my Fork Claiming Service: a space laptop with 2 Linux distributions installed in dual boot. The first is to work on, the second doesn't have internet and now has 5 partition images:
1. A fresh installation with VPN
2. A fresh installation with VPN and BCH full client, synced up to 2010, and set to prune. And BCH's Electrum Fork.
3. A fresh installation with VPN and BTG full client, synced up to 2010, and set to prune. And BTG's Electrum Fork (using wine).
4. A fresh installation with VPN and BCD full client, synced up to 2010, and set to prune. And BCD's Electrum Fork.
5. A fresh installation with VPN and eCash full client, synced up to 2010, and set to prune. And eCash'es Electrum Fork.
The laptop doesn't have enough disk space to keep all full clients.
This setup makes it much easier to handle Forkcoins: I restore the partition I need, boot into it, import the address/pubkey, and let it sync. When done, I take it offline, enter the private key, and create a raw transaction to transfer funds. After that, I boot into the second Linux distribution to overwrite the first partition. This makes offline signing relatively easy without ever risking the private key to untrusted software.
All this fits on 160 GB