Thank you for posting the samples.
Learning a specific calligraphic style is quite different from improving your penmanship.
With calligraphy, the goal is to replicate some pretty specific strokes and spaces.
The goal is to obliterate your penmanship quirks as much as possible.
With penmanship, the goal is to morph your writing into something that is more pleasing to your eye.
So you keep some of the quirks while adopting some of the characteristics from calligraphic styles.
Looking at your top sample - the strong points are consistency of slant, and a nice amount of space between the letters.
Compared to the bottom sample, it looks very nice.
IMHO, the area that needs the most attention is the *pinching* of the letters.
On the bottom sample, many of the letters are so compressed that you can hardly see any space within the letters.
On the top sample, several of the letters are lacking enough space (the space within an o or an a is called the counter)
Look at the e's - on some, I'm not sure that there is any space.
Starting a new style will not cancel out what you have learned from your Spencerian studies.
Don't switch back and forth on a daily basis. If you decide to try italics - maybe spend a month or so on italics.
Then, go back to Spencerian and see how the italic practice might have influenced your muscle memory.
Right now, your muscle memory is giving you *pinched* letters.
Some time spent on italics might help you to *inflate* the counters - and give the individual letters a little more oomph.
If you try italics, ignore the details on the ascenders and descenders. Just use a straight line. You don't need the serifs. Focus on the shapes that are within the x-height.
That's where you need to adjust the shapes.
The good thing about italics is that the almond shape is similar to the teardrop in Spencerian.
Working on both of them can be complementary - assuming you are doing an italic monoline - and not broad edge.
I would not recommend going back and forth between Spencerian and copperplate.
Your capital letters are gorgeous. I'd love to see all of them.
They are not pinched at all - so I'm sure you can pump a little air into your smaller letters.
Maybe you can do it without even going to the italics.
Another tip for improving penmanship is to force yourself to write with a larger x-height.
Just make the x-height larger - don't make the ascenders and descenders proportionate.
Leave them the height they are.
The larger x-height will give you practice at making larger counters - and then when you go back to the normal height,
you can maintain the more open spaces.
On the lined paper, the x-height is only about a third of the space.
If you penciled in a line at the center - and just increased your x-height by that much, you might see some improvement.
Hopefully, you will keep posting samples.
It helps others to see progress - and these samples show that you clearly have the ability.
Thanks again for posting.
To those people who say they can't read cursive - ask them to just try looking at each letter.
They can figure it out, if they just try.