Officerfriendly, I’m going to suggest something pretty radical here, and while it may seem a bit “out there” I’m certain it’s going to solve a lot of your problems.
You might want to sit down for this. Comfortable? Good. Are you ready..?
GO TO A BLOODY BIKE SHOP!!!
Not sure what helmet you want? Go to a shop, try helmets til you find one you like and that fits you, then buy it.
Unsure about which frame size to buy? Go to a shop, try bikes til you find one you like and that fits you, then buy it.
I could go on giving other examples, but I’m sure you get the picture.
Honestly dude, half of your problems seem to stem from asking for advice, then completely ignoring all of it.
I’d feel bad about suggesting this, as if it was anyone else they would perhaps stop posting such hilarious threads. However as it’s you, you’ll probably ignore my (and everyone else’s) advice, go on to buy something completely unsuitable, then post a follow up thread with a picture of a cushion strapped into a colander, asking why your new helmet doesn’t fit well, and is a bit sweaty…