Typewriter layouts are designed to avoid jamming, but not by reducing typing speed. They place letters that are pressed in direct succession apart, so that the levers don’t collide. Trained typists can write pretty damn fast on a typewriter.
I've always wanted a Blick, their "scientific" DHIATENSOR layout intrigues me. They also made a qwerty version and I seem to remember a story that their salespeople would make you sign a waiver that you were choosing a less efficient keyboard if you bought one. That's certainly 90% marketing for their layout and maybe 10% fact, but I find it amusing (if true, but I can't seem to find a reference to it any more).
I'll bet typewriter-trained typists can really move. It's definitely a separate skill, at least for the manual typewriters in my collection which have about an inch of key travel and a heck of a lot more actuation force than the gateron red switches I use at work. :-)
Ultimately I find that the fastest layout is the one you know.
... and that really reduces typing speed. When i switched to dworak I was amazed how my fingers just roll on a keyboard, forming sentences faster than I even form a conscious understanding in which succession should I move my fingers. It just happens as if by itself!! Just think of a word to type and it is already on the screen.
That may be the effect for you, but it's not a goal. It's maybe a tradeoff, but machine writing is a trainable craft. Usual results for trained people are at about 200 - 400 characters per minute measured over 10 minutes. Championship results are at up to 900 characters.
[1]: http://www.recordholdersrepublic.co.uk/world-record-holders/...