The resolution you use will impact this greatly. I run my iMac at 2048 x 1152. Makes a world of difference and is perfect for my eyes. At the default resolution I found items too small.Would you guys say 24 inches is the sweet spot for document work? I kinda find looking around a 32 inch screen tiring when reading.
I personally think 32" is the sweet spot for browsing. Document work depends on multi docs or not. For single docs 24" is probably just fine.
I think a lot of people don't alter the resolutions of their displays (when not happy with default) which is a big mistake.Why don't you set the 32" 4K to look like 2560x1440 retina equivalent? Should be pretty much perfect at that size/resolution. On my 4K 27" that resolution makes everything too little, on the other hand 1920x1080 makes everything a little too big.