The best chicken sandwich?

Ok, here´s a confession : I´m a pathetic roaster of chickens.
There, it´s out, and I feel much easier.
I can roast a bird with enough decency that it´s edible, of course. I would even rate myself in the "not bad" bracket sometimes.
But that plump, juicy bird, tender and flavourful, burnished like blonde mahogany and oozing pints of gravy? Hardly.
I blame my oven, which is the easy way, and have learnt to live with chickens in which the breast is delicious and not dry at all, and some of the dark meat is still slightly underdone.
We eat one of the breasts, both legs, the crunchy skin and the roast onions. I save the carcass for stock, pick the pinky not-that-good-looking dark bits for later use in creamy sauces or risottos, and jealously guard the untouched breast and the leftover gravy.
Because if I make indifferent roast chickens, my chicken sandwich is second to none, I think, and it´s what keeps me coming back to the oven to roast birds. Rotisserie chickens taste great, but I shudder to think what dodgy farm they grew up in, and what exactly is in that sauce.
If the chicken I have to play with has been poached, not roasted, then I go for all the heavy artillery of bacon, avocados and tomatoes. If the bread is only so so, then I toast it.
But when I have proper bread, from La Tahona, then I just lay a crisp lettuce leaf on it, and top it with the chicken.
Which, if it´s good, just needs some mayonaise, Helman´s for choice, perked up with lemon juice and a bit of olive oil, and the essential touch for it to be really sublime: a couple of spoonfuls of jellified gravy.
That gravy is full of chicken flavour, and of oregano and lemon and garlic and pepper, too, and it´s the touch that elevates the sandwich. I beleive it to be the secret ingredient in the ones they make in La Marina, and so am always careful to save the last drop of sauce and juice, even if it means smacking J´s hand as he mops everything up enthusiastically.
Of course if your roast chicken is amazing, then maybe you won´t have enough leftover for sanwiches, and that´s something you´re going to have to live with.
Unless your oven fits two chickens.