When you first start handquilting, it often feels like trying to rub your head and pat your tummy and dance a jig, all at the same time! Persevere, it WILL come to you. Practice makes perfect.
Consistency of stitch length is more important than number of stitches per inch, absolutley! 12 stitches to the inch is considered "museum quality", but 9-10 is highly prized as well. Nonetheless, 6-7 stitches all of equal length and equal between stitches is completely acceptable and makes a beautiful quilt.
There is a method of handquilting called "big stitch" quilting that uses a larger thread and a larger needle (necessary because the small eye of the "betweens" won't take the larger threads very well). This stitch is most like Japanese sashiko quilting stitches. Aiming for 5-7 per inch stitches is fine.
I most often use this big stitch method now because of arthritis/nerve-related hand, muscle, nerve issues. I like the size 3, 5, 7 Richard Hemming brand of large-eye Betweens for my threads. These betweens are longer and larger and easier to thread than other betweens. I can feel them better with my fingers. Occasionally I use a small sashiko needle. Use whatever makes the smallest hole with an eye that you can thread.
I use many different threads for my big stitch work: #10 weight crochet thread (yep!); #30 Sulky cotton thread; #8 or #12 perle (balls) embroidery threads; occasionally sashiko thread when I can find it cheaply enough online. I personally don't use the skeins of embroidery floss because I would want to use 2 or 3 strands of the thread and I don't care for the separation that can occur in the stitches when I separate into strands.
I use a 14" or 16" wooden hoop to hold my project. Many people can handquilt without a hoop; I am not one of them! I always hand baste the layers of the quilt with thread rather than pins because I don't like how my quilting thread gets caught on the pins. I turn the backing to the front and baste that down to stablize the edges and hide the batting while I quilt. This prevents the soles of my Reeboks from grabbing the batting, which they seem to love to do!
I use a rocking stitch, threading usually no more than 2 stitches onto my needle at a time. I can not use a thimble but use my fingernail instead because I already can't feel anything with my fingertips and hardly know when I have the needle in my hand as it is. Loading more than 2 stitches is difficult to push without a thimble.
On the rare occasions when I do wear a thimble I prefer my leather one over all the others I've tried over the decades. Thimbles are one of those VERY individual preferences, decide on your own.
Enjoy the process; I promise you will get better the longer you practice it.
Jan in VA