I'd get the largest oven you can afford. Oven space is usually the bottleneck for most extractors. You'll always want larger and or more ovens.
I do believe cascade probably makes the best ovens, and they're domestic which is huge in my book. That said, they are at least double the price of other competitive oven manufacturers. They are just too small IMO. Even the 1.9 is too small for large scale extractors. You can realistically only use 3 shelves on a 1.9 for your initial purge, as the muffin will far surpass shelf height.
For example, I poured a 395g run last night onto 5 sheets. Completely filled a 3.2 & 1.9
How many 1.7's or even 1.9's would it take to hold that? Particularly considering the initial purge muffin size. I'd love to get a Cascade. I'm just not sure if it would be worth it when dealing with larger scale production.