How would I go about making this fuselage?

this is my first post on here.

I am working on making a 3D model of the Hawker Siddeley Nimrod.
I have used some de Havilland Comet blueprints for the main part (because the Nimrod is a modified version of the comet) but the problem is, the Nimrod fuselage is made up of two cylinders and I am having trouble making it look good.

Here is what I currently have:

And here is what I am trying to do:

As you can see, the parts appear to be jagged where they intersect.
I am also having difficulty with making the two parts appear to be smoother and connecting at the front.
My priority, however, is removing all of the parts of the bottom object that intersect with the top one, without any shading issues.

I have tried using the Boolean Modifier to subtract the bottom half from the top, however this caused shading problems.

Sorry if I was not clear enough.

Also, I need to be able to solidify the top half (I am making this for Roblox)