I have been doing what I call zone spinning, which means I just spin the fiber on my electric spinner, while watching TV, and let the yarn be whatever it wants to be. I stop and pick out VM but other than that, I don't fuss with the roving to force it into thick or thin or a specific type of yarn.
I tend to think I spin pretty much the same type of yarn when I do this. My electric gets set at about the same pull in, and speed. And I get a two ply yarn that looks very similiar, but I was surprised to find how unsimiliar the yarns can be, just changing the fiber being used.
What I did was to take two oz balls of roving per bobbin, and then ply that. I did five different fibers, and took some measurements along the way. That's how I found out how different the fibers made the yarn.
Here's a closeup picture of the five different skeins.
The white corriedale on the far right is from this roving I have posted a picture of this before, when I got it back from Woolyknob fiber mill. That skein is 163 yds, 18 WPI. I had a big difference between the WPI of the singles of the two bobbins, one was 25 WPI and the other 32. I must have gotten more into spinning finer as I went along.
Just left of that is the CVM skein. I bought this roving from Little Barn, and as you can see in the picture, CVM is like merino. It is a very puffy, springy yarn after it is spun. The skein is 162 yds, and the 2 ply is a thick 10 WPI.
In the middle is a Border Leicester that I bought two years ago, and had processed by Woolyknob. The singles were closer at 22 WPI and 24 WPI and the 2 ply is 13 WPI. There is only 120 yds in the skein, being a thicker yarn. I did overspin some in this yarn, I am not sure if it was because I was picking out VM (the electric just keeps on spinning, and sometimes I try and cheat and pull the VM out without stopping the spinner). I think the yarn will relax some when I wash it.
Left of that is the llama that I had processed by Woolyknob. It was an interesting roving. There were very obvious white guard hairs in it, which looked like stiff sewing thread. I could pick them out easily, if I stopped, went over the piece of roving I wanted to spin next, and pull them out. Also this roving had the most VM, llamas and alpacas just love to roll or lounge in the hay. It'll make this yarn hard to use for anything next to the skin, the pricklies still can be felt. The singles spun at 25 WPI and 21 WPI and I had alot of trouble with thick areas happening in the yarn. So the 2 ply is a 13 WPI in a 145 yd skein.
I saved my favorite for last, the brown Border leicester on the far left. I bought this fleece at SAFF, and had it processed at Woolyknob. This spun into a very consistent yarn for me, with the singles at 24 WPI and 23 WPI. The 2 ply is 17 WPI, so I have a larger skein, 173 yds. I love the color of this yarn, a true deep natural brown. I will be making a sweater from this roving, I am sure of that.
The whole point to all this was to see how each of the rovings I have recently purchased would spin, if I was spinning them 'in a hurry' If I plan to make any big knitting project that takes over 2000 yards, I need to be spinning in the most productive method. The CVM would not work, it is too easily too bulky. The llama will not work, it is too itchy. The corriedale will be OK, but needs to be dyed, I am not into white sweaters. And the one BL, will be OK, I may think about a barn sweater, or something felted with that, I am concerned that the yarn would just be too bulky for a shaped and cabled sweater. The brown BL is the winner, now I just have to work on making another 12 skeins _just like it_ :)