Hi Lupine,
I asked this question before too and do not get an answer. But I am afraid that the 16core Mac Pro 2019 (with 192 or 96 Gb of Ram) is the best choice. I own a 12core mid 2010 Mac Pro with SSDs, 96 Gb of Ram and all but the processor speed of the single cores seems to be too slow for Synchron. I considered the iMac early 2019 but it only has 8 cores and is limited to only 2 Thunderbolt slots on one bus. The 10core iMac Pro is still a option because of it´s Thunderbolt slots but with enough Ram it´s nealy a costy as the Mac Pro 2019 and not as future prove. And the new Mac Pro is silent like a husband after 10 years of marriage.
If you don´t need an expensive GPU would recommend the Mac Pro 2019. But who am I haha. I was asking for advice too.
Let´s see if some crack in here will share his or her wisdom with us.