"Using a start charge for a Jacketed bullet for a cast billed of the same weight, when cast load data is unavailable, is pretty common."
That I will agree with!!!
The rest, not so much, and every gun will be different, and every reloader has the responsibility to not offer 'Suggestions" on what may work or what they "Heard"
And the one looking for data, especially on the internet from complete strangers, has the responsibility to find published data, or to work up their own loads and take responsibility for said loads