Europeos, ok, so I agree that you have the right to have a lot of high levels in 1 alliance.
I do think that if you make that choice, you need to understand the limitations that will give you in terms of opponents. There are not a lot of alliances with only high level players. For a fair match, you may have long war search times, or may not even find anyone at all.
I do not think players have the right to put a lot of high level players in one alliance and then add irons/decoys/sandbags so that they get matched with lesser alliances. That is greedy, selfish, and poor sportsmanship.
You can't get everything you want. Certain choices mean you will have to accept the limitations of that choice.
I am sorry that there isn't the perfect solution for you, but there rarely is a perfect solution.
We just started a second alliance: it is composed currently of really low level and really high level. I had a choice. I could put everyone in a war and potentially inadvertently manipulate a match up or I could leave some at the top out or some at the bottom out. It was a choice. I did not want to make my problem someone else's problem, so you can probably guess which one I chose. There wasn't a perfect solution as is life.
Now, if you REALLY must sandbag, this is what I propose: The next time you get matched with an alliance that isn't not sandbagging, your top guys do not attack (however many sandbags you have), and set up their base to be a giveaway. If you are as skilled as you say, this will be easily achievable for you. I look forward to your screenshots as proof of this. This proposal is said in all seriousness. I am not joking, nor trying to call you out/ be an *ss, or ____(fill in with whatever.) AND, if you achieve perfect without your top guys attacking, then I think it is fair for the top guys to still attack, but only AFTER perfect is achieved.