I don't know what's the motivation in using "0039" though, maybe because it's intended to replace BIP39.
In BIP39, the 'entropy' is used to generate the 'mnemonic sentence' (seed phrase), then the 'binary seed' (seed) is generated from the mnemonic sentence - (learmebitcoin - BIP39)
while in SLIP39, the 'binary seed' itself is used to generate the mnemonic sentences (slip-0039).
Now in iancoleman's tool, try to paste BIP39's "BIP39 seed" to SLIP39's "Master Secret" and it should generate the same set of addresses when restored.