I’m your rebel…
Most stouts and porters are essentially identical in nature. Ingredients don’t matter, they both can use all the same ingredients. Taste the finished beer. Is your stout not stouty enough, for YOU? Call it a porter if you prefer. Did you make a really powerful porter? Great! Call it a porter if you want, or a stout. If you serve it to somebody blind and they don’t know the style, they’d be hard pressed to tell you which style it is, i.e., no one really knows the differences, seriously.
Personally I think of Guinness as the absolute wimpiest version of either style. More like a lite porter (but not a brown porter, mind you).
After reviewing several BOS and award winning stouts and porters, and seeing that they often have upwards of 10-12 different malts, I now brew mine the same way, always as a kitchen sink sort of brew. Down below I’ve pasted my latest iteration, I tend to use whatever I have on hand at the time, and they always turn out great. I mean, you’re not worried about color, black is black, so anything goes. Keep it simple if you like, but I like mine to taste deeply interesting and roasty. I tend to go a little heavy on the dark roast to suit my own taste. And like you, I don’t use much crystal malts, don’t want it too sweet. I also now always toast some of the Maris Otter to give a beautiful peanuttiness, tastes identical to peanut butter, which I don’t want too strong so I limit it to just a few ounces.
I have given up on oats; they’ve done nothing for any of beers ever. I recently brewed a 50% oat witbier (no wheat!), and it has very thin body, zero head retention, doesn’t taste “oaty” at all, and is nearly crystal clear. And the mash AND boil were the stickiest gooeyest mess I’ve ever seen, but the finished beer, thin!! In other words, oats don’t do anything you think they do. So now, for my stouts, I use wheat or rye anytime oats might otherwise be specified. In fact I won silver in a competition with the following recipe for “oatmeal stout” which contained zero oats at all. Here it is:
And I can explain reasons I used many of these ingredients:
Roasted barley, chocolate, black patent - yeah, you know why.
Rye for body and head retention.
4 oz crystal malt, I figured sure, why not. Not like this will be overpowering.
“American Two-Row Toasted” is actually toasted Maris Otter. Tastes like peanuts, I discovered many years ago, always works like a charm.
Victory malt, a little biscuit complexity if it weren’t already there from the toasted MO (probably was anyway).
German Chocolate Wheat, I think I used just because it was laying around and I wanted to use it up. Perfect fit in this style.
Phoenix, I had laying around too and used them up.
WGV, same thing, but what a perfect fit here.
I think any kind of hops can be good in a stout or porter, if not overpowering anywhere near Black IPA levels. However I really do prefer the English style ones including American equivalents like Willamette, which is one of my favorite hops of all, I use it a lot and in any style.
Yeast is always like whatever I have laying around. At first taste I was very skeptical of my choice of Munton’s Ale Yeast here, it was extremely fruity at first, but after a couple weeks this mellowed and left just slightly fruity undertones that I found pleasant. Honestly I used it because it was cheap and I wanted to try it for a while. I think Munton’s was like $2 or $3, MUCH cheaper than anything else out there worth trying. If I had my pick of any yeast, I’d probably go with Lallemand London ESB or S-04, either would do very nicely here, or their liquid equivalents. And US-05 wouldn’t be bad either of course.
So that’s my spiel on the dark ales, for now. To further answer some of the other questions and comments in this thread, randomly:
I like beers with brown malt in them, but haven’t used this much myself yet. I would like to use it more in future. Seems a unique flavor that you just can’t get anywhere else. It will take some time to “get good at it”.
As I said previously, I like to go heavy on the dark roasted grains. I don’t know if 10% would suit my fancy or turn out blacker than midnight enough for me. I like my current level of about 17-18%, turns out wonderful. Any combination is fine by me, well except maybe limit the black patent to 2-3% at most or it can taste ashy.
pH is something to watch for in these brews. You’ll always need to add some baking soda or pickling lime, otherwise the finished beer tastes tart and can have a green olive flavor, which I’ve experienced MANY times from MANY different brewers over the years, it’s a real thing. And aim high. Mash pH should be about 5.6 as measured at room temp.
Mash temperatures are always a matter of personal preference. I change it up sometimes on a whim depending on what I think I’ll want for this particular batch. But a couple degrees does nothing. Set it to 148 or 153 or 160 F if you want dry, middle, or drastically fuller body, respectively. Totally up to you. I probably prefer low to middle of the road, hence my selection of 150 F for this and for most beers I brew.
You’ll see my ABV in the recipe above was only 4%. But again, it just depends. Brew whatever you like. I’ve brewed Russian Imperials, I’ve brewed brown porters, and everything in between. It’s all good. Yes, porter and stout is some of my favorite beer. And I’m blessed(!?) with alkaline water from the tap, so for this area to use my tap water here, these are basically the best suited styles for me to brew without major adjustments to water and pH.
Okay now that’s all… for now. Slainte! 
