Jmxcpter,
As you can see the opinions of ideal sharpening set are quite different. Taking into consideration that most of fellows here are knowing what they are saying - here is only one logical explanation.
This is mostly the question of individual likings and here is no objectively best solution. For example, I can sharpen each knife shaving sharp using only some $ worth silicon carbide stone and the bottom ring of porcelain dinner plate. Another question is how long time it will require and how pleasant and comfortable my work will be.
Well, now I'll try to mess your task even more

What are you going to do - real life sharpening for working knives or sharpening for itself, just as state of art?
If first - my working set would be:
DMT coarse (blue) Diamond Whetstone for edge reprofiling, 6 inches is enough for 3-4" long blades. 8 inches will bring you comfort with these blades and allow to sharpen up to 6" long blades without any problems.
DMT fine (red) one with the same dimensions to obtain fine working edge, shaving sharp.
You can save some bucks purchasing double-sided Diamond Whetstone, Duo-Sharp if I remember properly, instead of these two.
For real life conditions it is quite enough and it will work better than arkansas whetstones. Natural arkansas stones work nicely on carbon steels or relatively soft stainless steels but they cause additional effort and decrease sharpening efficiency when sharpening blades of modern extreme stainless steels like ATS-34/154CM or CPM 440V. They also wear faster losing their flat plane with these steels (maybe I have not-the-best stones).
If you want to obtain more-than-enough, really extra-fine edge add SPYDERCO fine Bench Stone to this set. Or the set of SPYDERCO ProFiles if you have a lot of knives with recurved blades. You can purchase this addition each moment when you will decide that previous set is not enough for you.
If you want to savor the sharpening process as itself - add SPYDERCO extra-fine Bench Stone.
WARNING: it is quite expensive and adds practically nothing to your knife real life performance comparing with finishing on SPYDERCO fine Bench Stone. But sometimes it is pleasant to put really mirror polished edge onto your
gentleman's carry knife no matter does it add any performance or not
If you want to save some bucks more you can replace DMT whetstones with Eze-Lap ones with the same grit. Probably they would last a little shorter but they cost about half of DMT price. However if you do not sharpen at least one knife daily I doubt you will notice any difference in durability.
BTW, it is no
medium grit DMT stones...
8" vs. 10".
10" allows more comfortable work, however the difference is not essential since you are working with 4-5" long blades. But 10" Diamond Whetstones are much more expensive!