another thing you can do is create the modpack on the Technic launcher as it is much easier than trying curse when you have FastCraft in it.
Even if someone wanted to include fastcraft into a curse modpack, it actually is not possible. Unless it is either added to the list here: https://docs.google.com/spread…F1OKy56cHxKNdk/edit#gid=0
And this is what is says on that page about fastcraft for curse:
"Since everyone keeps asking: Fastcraft and IndustrialCraft2 include conditions we cannot enforce. We cannot add them to the list at this time."
So through that method, it is not possible unless the license was adapted, but I think that is not what Player wants with his mod.
the other option would be Player mirroring the download on Curse Forge which would then allow curse modpacks to use the mod. and when he has a new version. he could completely delete the old versions (not archive, actual delete) leaving only the newest FastCraft available to be downloaded. If the pack authors don't update the modpack, then theoretically it would fix all curse packs from distributing an old version of the mod automatically since there wouldn't be a file to download. Plus it would give you a tally of how many people are using fastcraft which might be nice. But again, that is completely a decision up to Player.