Sorry. Had these conversations before and most of the time they go nowhere, and I've been too busy at work to even log on to FABO.
First thing you probably don't want to hear is that engine should not need or want 20 deg initial.
In fact discussed this with on a thread a few a months ago, it might have been with you, where the engine was on a test stand.
As stated above in this thread. No load on the engine doesn't tell us much about what an engine will need when loaded.
An engine load is based on the percentage of power being used versus the max it could make at that rpm.
If it takes 10 hp to turn the transmission pump and the engine with accessories is making 20 hp net at 600 rpm, then 10 hp is causing 50% load, which is fairly high.