Yes, agreed, and I'm pretty much following that approach to the letter.
I have the Zemlin hood and lens cap on order, but I don't know if they will arrive in time before a trip I have later this month. I also have the LensCoat TravelHood and Hoodie on order (arriving on Monday) that I can use if the Zemlin gear doesn't arrive in time. They will also provide additional traveling options, that may allow me to fit my 600 TC in other bags that may be better suited for hiking, but less suitable as airline carry-ons (like maybe my NYA-EVO 60-C, or the 50-C when it arrives).
Regarding which size of GG Kiboko bag one should get for fitting a 600 f4; I was concerned enough about the loss of depth that you get with the laptop model, that I decided to order both models and do some sizing tests with my gear. Then I plan to keep the one I prefer and return the other one. Guess which one I am sending back..., Yep, the 30L+ (laptop model).
I test fitted both bags with my Z 600 TC with the OEM hood and lens cover. So this is the worst case scenario, as I could go with slimmer options. (once I have received the alternate hoods and lens covers). I was able to fit the lens and hood combo in both bags and zip the top flap closed, but it was definitely a struggle with the 30L+ and I could feel some bulging in the back panel when I put on the backpack.
I didn't even try to fit my 16" laptop in the 30L+ with my 600 TC lens inside, because the bag was already bulging too much without it. But I did confirm that a 16" laptop does fit inside the dimensions of the laptop pocket (if the bag is not overly packed).
I'll include a few iPhone shots I took during my fitting tests. When the color is visible, the gray bag is the 30L+ and the Sahara bag is the 30L.
Measurement of the depth from the floor of the insert to the hinge of the flap (30L) :
View attachment 88294
Measurement of the depth (30L+) :
View attachment 88295
Folding the top flap over loosely (30L) :
View attachment 88298
Folding the top flap over loosely(30L+) :
View attachment 88303
Measurement of the gap opening before zipping shut (30L) :
View attachment 88302
Measurement of the gap opening before zipping shut (30L+) :
View attachment 88304
I didn't take any pictures (yet) with the bags zipped shut, as I wasn't sure if the differences would be noticeable (also I was just documenting the test results for my own use in determining which bag to keep).
In the end, having the greater interior volume that's available with the 30L was quite noticeable and I value that aspect much more than being able to carry a laptop in my camera bag The fact that the 30L is slightly cheaper is also a bonus.