The etsy fan was way too loud for me. I have an extremely quiet rural house. I bought this and it is silent, period! Fits right on top of my trashcan and the silicone feet will not allow it to slide off. On both low and med speed - just quiet. Whether it fits on the Arcadyan is unknown to me - I am just recommending the fan for function and quietness.
Did the fan help me? All metrics improved except speedtest. Go figure. When it gets warmer outside, I will try again.
I have run this fan since April, placed on the bottom with the 'trashcan' on top of it. Works great and no problems with any excessive heat. Sure, maybe you could make the sides a little more airtight, but don't over engineer the solution.
https://www.amazon.com/gp/product/B00G05A2MU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Does really matter if the chamber heats slowly, as long as you can get there and stay there? I used a 21W seedling mat in a styrofoam box and got to 65C (at least near the surface of the mat) in about 1/2 hour. Two of these heaters with this fan blowing through them gets a 2' x 2' x 18" box to 60C+ in about a minute for me. The large containers of liquid (garum for example) get up there in about 15 minutes. That's what I'm using for my garums right now.