I don't think you can? You might just have to cooperatively close it and reopen another if it's that there's less than ~600 Satoshi in your wallet?

But youll need around 0.003 to open a new channel.

Either he got it wrong or added the channel opening transaction fee.


You are missing one thing. Channels are supposed to be used more than once. Most people use the Lightning Network for small transactions which would be cost-ineffective to send via an on-chain transaction. Larger payments are also becoming feasible thanks to increasing network's liquidity and multi-path payments. Opening a channel for a single transaction is completely pointless.

That error was due to your attempted open channel's fund is lower than 0.000547BTC.
You'll get a different error if it's lower than Electrum's minimum which is Exception('funding_sat too low: xxxx < 200000')

Unfortunately, there's no settings to override it.

I prefer it that way, because if the channel's funds is too low, users will end up opening channels more often if they need to send more funds.
If it's 0.002, they will only need that channel to transact LN funds given that the remote node has enough connections.

Plus, you can get your Bitcoins back to onchain funds and get inbound capacity though "submarine swap" feature which is very convenient to use in the GIU.

For now, I want to open channels directly with my contractors, and make regular monthly transfers, let's say, and save on this by closing channels once a year, let's say. This way I won't have to pay extra routing fees, right? Then I can launch my node, so that these fees between their channels were not higher than 1 Satoshi as now I translate picking up time in the network when there is no excitement

0.002 plus the fees to open a channel.
Then use "reverse swap" to get some of the funds you don't need back to onchain, but that process comes with a fee of 0.0002+ BTC.

Or launch Electrum with -testnet argument to use testnet's chain for testing purposes.

0.002BTC being "good enough" is my personal opinion like I said above.
Other wallets however, will let you open a channel with lower amount IIRC maybe Electrum devs would reduce this in the future.
I can't recommend others though since I'm not using them.

BTW, long-term saving with that amount though LN is a no go, I suggest custodian wallets for amounts like 0.00069376 a year.
Reason is, you can't receive at all if you don't have inbound capacity, read this thread for more info: Electrum Lightning Network walkthrough: Receiving a payment

No, LN is only available for [standard] Native SegWit Electrum wallets.
Read the thread I linked above to learn more about the usage of Electrum's LN feature: Electrum Lightning Network walkthrough

Testnet funds have no value and in a separate blockchain than Bitcoin's and the testnet wallets will be saved in a different directory.
You can easily get funds using testnet faucets: List of Testnet BTC Faucet

Because, you'll have to pay a fee that might take a portion of it to spend that balance because you'll end up with lots of very small inputs.
Transaction fee will be based from the fee rate (which you'll set in the wallet) and the transaction's virtual size which will get higher if it has a lot of inputs.
1sat/B is still good enough to consolidate them though.

Custodial wallets will just send from their hot wallet when you want to withdraw (minus their fee which can be cheaper for low-priority).
Personally, I'll use a custodial wallet for that amount.

LN is a very good choice however won't let you receive 'savings' from your 'clients' unless you have enough inbound capacity.
And you don't have enough funds to open a channel of 0.002 BTC then use submarine swap or spend some satoshi.
You need to find a way to increase your inbound capacity like mentioned in the previous sentence.

I don't get it.
But everything you can do with mainnet, you can do the same with testnet.

How do I open my multisig wallet on testnet ? So that the funds transferred from it are transferred in a test way and not in a real way

Okay, so that's the issue in the "Lightning Network Walktrough" thread is all about.

Unfortunately, I haven't found a way to open channels between two Electrum wallets either.
I have tried adding the "IP Address" but it always results with "Timeout" or "Cancelled Error".

You can try it: instead of using just the nodeid, follow it with an '@' sign then the PC/ISP's IP address like for example:
0369c4ddc6076646ddf30ad58c4beca8eee399557063f69a17xxxxxxxxxxxxxxxxx@17x.1xx.2x.4x
Both Electrum wallets should be active.

I don't know if it will work in the first place since I haven't successfully opened a channel between two Electrum wallets yet and AFAIK there's no related article/documentation to point you at.
So I can't walk you through that particular issue, sry.

For now, try to use the remapped address instead of your ISP's.