There are still two players left unsigned from BA's Top 50:
34. Fernando Villalobos, C
45. Jose Bonilla, SS
https://www.baseballamerica.com/stories/where-the-top-50-mlb-international-prospects-have-agreed-to-sign/
The non-board league that BTS, JFL, and I participate in went to one-hour clocks for the back-half of the amateur draft and it worked really well.
There's definitely nothing wrong with 6-hour windows, imo.