You are quite right about the thick tension wheel on my Royal.  It is thicker than any of my other typewriters.  I'll look into finding a Royal manual, thanks for the suggestion. 

And, my Remington 30 is actually a 30-30, also.  I thought they did that double-30 business for the fun of it.  Haha.  I simply call it a 30 and be done with it.  I do have an antique print ad from "The Literary Digest, Sept. 19, 1925" advertising a nearly identical looking as my Remington 30-30 except the ad image has a standard size carriage, otherwise it seems to have all the same keys as well as a 10-key decimal system.  On the bottom of the ad it says "Remington Model 30."   They did not duplicate the 30 at least on the print ad I have, only the typewriter image has 30  30 (as does mine). 

Thanks, too, for the suggestion to keep the typewriter since I have often thought about getting rid of it (I have never worked on it to try to get it working again; it's the only typewriter I have that I've pretty much neglected to bring back to working life).  I've had my Rem 30 for decades, I don't even know where I got it from but I was a teenager when I did get it, and probably for very little money since I had none at the time.  I'm retired now.  It's rather surprising that it's still with me after all these years.