A 300mm is considered a normal lens for 8x10, equivalent to how the eye sees the subject, or the distance between furthest corners of the frame. A 150mm is that for 4x5. Roversi work is probably shot with something longer than normal by the look of it. Thank you for introducing him to me. For 8x10 I use a 250mm, 300mm, 450mm and a 600mm. 300mm is a good place to start, but 450mm would probably be closer to the portrait work you admire.
Many people like to stay with the same brand of lens across the range so that the "look" of the lens manufacturer is the same in all their work. My 450mm is a Nikkor 450mm M f9. Perhaps that would be something to look at. That is a popular lens and often shows up for sale here, the LF Forum or eBay.
Here is a link to the most recent one listed on the LF Forum to give you a look at one and a pretty average price.
You are moving up in format now. It is a slippery slope. It is not out of the question that you will at some future date move up again. The 300mm Schneider has enough coverage for limited movement on 8x10. It will not cover 11x14 or 7x17. I bought a 300mm Schneider for 8x10, but soon went to a 300mm or 12inch Dagor for the coverage needed in 7x17. To round out my list, my 600mm is a Fuji C. All three of those will cover beyond 7x17. I think up through 12x20.
Be sure that your new camera has enough bellows length for what ever lens(es) you consider.
Hope this helps.