For GPU thickness, however, please push for compatibility for RTX3090 FE (3 slots, passthrough fan) with vents on both sides...this will be as if you are in open test table...then sentry will offer a master piece of cooling for passthrough GPU.
I think pasthrough GPU is a great opportunity for small case like sentry.
2.5 slot is something worth considering, but 3 slots is too much. It will not be like open test bench because perforation is reducing the airflow and on top of that the perforation is not everywhere so it'll still slow down the air exchange.
The way the perforation affects the airflow is not just that you have the vent and so it's like open air. By making perforation you are reducing the area of exchange, so from the top of my head let's say we start with 50% or 60% which is already a significant difference. On top of that air in each hole behaves in a way that at certain distance from the edge it gradually slows down, has gradient of speed within that range, so roughly, by average that area has the flow less than half of the airflow in the middle of the vent, so effective airflow is even less than just the area. So generally huge holes are better for performance and that is that magic trick that some use for their custom cases like NFC, but then the EU safety regulations come into the picture where we can't have, don't want to use this kind of design.
If you have a case that has 3 or 4 120 mm fans and huge vent in front of it, then you have more exchange area right at the beginning, so the base area for the effective area function is significantly bigger than what we can have in SFF cases. If you watch Gamers Nexus videos on tower cases, he's often bashing stupid ideas like making full TG front panels with small vents where you literally buy a case to have multiple fans for huge airflow area and close them up with a solid front panel. Those huge power hungry triple slot cards are made for proportionally huge well vented cases.
Handling 3 slot cards means no support for 2.5" drive or increasing complexity of centre rail to somehow mount the drives there, the 3 slot cards being choked anyway and having fans causing a lot of turbulence as there would be not much space between fans and perforation. On top of that a flexible riser or a really tall 90 degree riser piece, reinforcing the case in some weird way at the corner where we have the cut-out etc. This is a complete makeover just so very few that have the cash for a triple-slot 3090 can boast that they did squeeze that inside such small case just so they can play at performance level of 3080 or even 3070 because the card is choking.
Be reasonable and think about that we initially designed the case for 150W TDP cards and you want to squeeze in a 350-400W cards inside...
What we want to do is to increase performance and compatibility with 2.5 slot cards, not just enable squeezing in something that doesn't make sense.