Replacement transaction underpriced

[iboxgithub]

Hi,

I read ethers-io/ethers-ens#9 and it seems understandable that by sending too many Tx to a Ethereum node, a Tx in the Mempool would not specifically queue the next one, thus provoking a nonce duplicate then generating the "Replacement transaction underpriced" error.

Nevertheless, what is the current best practice to queue these Tx?

1. As straightforward as queueing them on my client and waiting sequentially for all of them to execute?
2. or is there an industry standard I am not aware of?

My issue is that I might have thousands of Tx to send per hour so at the minute so if I take option 1 it means that I need to literally create a load balancer for my transactions.

thanks for your help!