There are indeed a lot of sloppy fists out there, it is an art form and everyone has a unique style. My rig has an auto keyer along with doxens of common sent messages - it feels like I'm hardly part of the experience letting the auto-sender transmit my call, location, etc.
A good mounted straight key is all you need until you get up around 30+, then a duplex really helps. The best practice is trying to send endless dots and dashes in streams at different speeds to "Muscle Memory" your wrist to the spacing, then all the dot and dash combos "L,q,y,f,r,z,k,p all let you switch - this is where you develope a code style, with your combo-letters and puctuations.
Yes, numbers are hard because you brain has trouble with 1-6, 2-7, 3-8, etc, iyour mind programs for letters and all of a sudden, an extra character is tossed in, putting up a roadblock.
Only last thought to copying, once you reach a steady 10wpm, put down the pen and listen to it, you should start hearing words in your head, not letters - by 13wpm you surely will.
I know you'll do good. But the online generator with copy and pasted forum posts id FAR FROM RANDOM and should be helpful, even though it is clean code, you can develop an ear for wrist later :)