Canon flash setup question

So, I bought 2 600EX-RT's and a ST-E3-RT. Through a strange series of events I ended up with another 600EX-RT. I have two inexpensive stand/umbrella setups for use with my flashes.

I don't do a lot of photography with off-camera flash. I use them for occasional informal portrait stuff. Mostly of my own family or occasionally close friends on request. I also I am trying to do a better job at product photography.

So here is my fundamental dilemma. I feel like I have more flash equipment than I really need.

I was thinking of keeping the new 600ex and selling the ST-E3 but I sort of like how easily the camera handles with the ST-E3 on it as opposed to the full sized flash. So now I am leaning towards selling the 3rd 600ex but am curious if there is a use for two off-camera flashes plus one on.

So I decided to reach out to the flash experts here and see what everyone thought I should do in this situation. I technically could keep them all and the ST-E3-RT but I am not sure I have a use for 3 off-camera flashes.

I can easily think of a reason to have 3: main, fill, rim/hair/background lights

Or: main [1], fill [reflector], rim [2], background [3]

... or the many other combinations

If you do product photography then three plus the STE3 is a good kit.

Here is a setup shot and the result from a food shoot.
There were 4 600EX-RTs used and an STE3 on the camera to control them.

For table top work the 600s and STE3 are preferable to monolights because of size. Plenty of power when this close. And I really like the Westcott knock offs as modifiers.

if you can afford to keep all three and want to continue in portraiture and product photography do it. Otherwise, if it wont get any use or you need the liquid cash, you can sell it and get another one if you feel the need.

If you have 3 this is what I would do:
Use 2 together as main light and 3rd as rim/hair light.
If you don't need money immediately keep them. It is a new system, it will be around for a while and you'll never know what you will need in the future.
Once you get the kick of speedlights, they are fun to play with.

That is what I do with my 3 x 600 and ST-E3. I would not sell any of that gear unless you need the finances.