The size of the chandelier often depends on the volume of space and if the ceiling planes are slanted. This chandelier below is 42" Dia.

I have never used the formula for lighting since the style of the light, that actual volume of the space have a lot more to do with the placement than the formula. IMO in a space where the light hangs in a space with a25' ceiling that light can be huge and please make sure it lights the room not the ceiling . I need to see the choices you are working with for sure . Also your style what other lighting you are planning. This all has to be considered . I actually rarely like chandeliers in LRs In a space with 25' ceilings that light will sway too so aware of that I use cable lighting often in this type of voluminous space so thta the lighting actully is at human height . I know the center light can be a fabulous bu what it actully provides for lighting is also neccessary so lots of bulbs for sur eand IMO all LEDs so changing the bulbs is not a yearly issue.I need to know oyur style mountain cabin can be many styles .

Thanks for the insights...the living room top view and the some pics as it is being built -

any ideas on chandelier size? and height of chandelier?

I was looking for some on the below website -

https://www.galleryhomecenter.com/products/wrought-iron-vintage-barn-metal-camino-two-tier-chandelier-chandeliers-industrial-loft-rustic-lighting-w-63-h-60

@BeverlyFLADeziner what is the size of the chandelier above that you have placed? what is the width?

In real life it's 40" but I cannot swear that's the size I have inserted into your pictures.

At a rough guess, i think is close to 60” as placed in the picture.