Mine was an 800 before I removed the glass - the main fan section is smaller of course so I presume that it’s the actual canopy that makes the difference ie if the extractor canopy is 800 with an 800 hob then most of the steam that rises, should hit the top of the canopy and be drawn towards the extractor. Even though we removed the glass on ours, it will be set into a suspended wood canopy so in effect, the steam should do the same thing. I’m told induction hobs are super steamy, ha ha. We got a Neff extractor which is also v quiet so hoping it does the trick!

Thanks for the comments. I will have MVHR system in the house so hopefully that will act as the extractor. I will need a recirculating extractor whether its on ceiling or in the hob. Benefit of gas over hob is more a personal preference. we like the Asian cooking better on flames instead of induction.

Mine is an AEG and surface mounted. I would think that is the most common but people do ask specifically for flush so there are no ridges for crumbs to sit under. Quartz and Dekton are hard.

One of the most basic rules for kitchen Islands is no hob unless absolutely necessary. Are you planning to extract under the floorboards? I'm assuming that you do have floorboards and not a concrete floor? With reference to your unit conundrums, visit a high street DIY store and ask them to plan you a kitchen. They might present solutions that you can take back to your designer. Also, when you see that you can get a kitchen of equivalent quality for a fraction of the price, you might save a fortune.