First, a few things.. The Juzek brothers were BORN in Prague, period. John/Jan was an individual maker, maybe in Prague. ALL of the Basses from Juzek were made by OTHER shops, first in Shoenbach (Czech., German border) and or neighboring Markneukirchen (east Germany) and later in Bubenreuth, Bavaria after the 2nd war. So there are the facts about Juzek. The models they 'bought' were quite common in shape and wood that were made by several bass specialist's shops in those areas. Some could be made from supplied parts between Germany and Shoenbach. Most were supplied to Juzek in New York (where they were based) from Europe and a few came from a neighboring seller in NYC from what I have read and then labeled. The Labeling was done in NY, not Europe unless it had a label from Anton Wilfer (earlier) or Wenzel B. Wilfer (later) and this was only the top of the line Italian models of which I have owned two, one from each maker. The second purchased directly from Juzek in NYC that was old stock and not for general sale as I knew that bass for years and they finally let it go when I asked to buy when I was a young adult having known that bass since High School. The Wilfer family as well as Benedict Lang were two of the suppliers to Juzek. Robert Juzek, the brother of John, ran the operation. FYI, there probably isn't a single Juzek instrument from Prague that was sold by that business ever except maybe a few violins that John may have made in Prague in the beginning. This includes all of the Violins, Violas, Cellos and Basses. In the 1934 catalog, it is still a full range music catalog selling everything from violins to tubas, drums, guitars and accessories. Maybe that changed at some point but they mainly supplied the School systems in and around New York. I was living and going to school in MB Florida when my music teacher showed me where to buy a bass when I went to NY for the summer to work for my Uncle. I was in the 8th grade then. So, few living people today know as much or has had as much contact with the Juzek family and their business than I have. Not that I know the most of anyone, but I know a lot from personal experience. I still continue to learn more as time goes by and I see more basses. Some with other brand markings that look similar to others. It is like putting a puzzle together from pieces you find over a life time that you will never ever complete because no one knows where all the pieces are or if all the pieces even exist. That is what the supply business was like from Europe in that area. Anonymous makers and suppliers with various labels in them to sell as a particular brand.
So, both your basses are similar. Round back with sloped shoulders. These are basses from the turn of the century and onwards. Only a close personal inspection can tell if it is 1890 or 1930. The Neck on top of the block that you were told is a Mittenwald style is actually more of a Guitar style in making that was used all over Germany at one time. Maybe Mittenwald kept it longer but the German/Czech border makers did all sorts of things individually and together with cross border parts supplying either side. It was cheaper to make in the Czech area than Germany for business but when hard times hit, makers in Germany supplied parts to the Shoenbach makers to stay busy and feed their families in the winter. This I have read about.
Also, most but not all of the older Mittenwald basses have flatbacks, not round. Both of your basses look to be from the same area or if one is Mittenwald, it is made in the same model. The gears however are those used in the Saxon area and not Mittenwald so that bass might just be an older Saxon bass by a few decades.
That is my assessment from the pictures. Nice functional basses. I have one from a slightly earlier date as well that we are currently re-setting the neck on and will be back shortly. They are similar but this one was made in the shop of the maker and slightly older. The Gemunder brothers imported basses like these as well in the 1890s. I have seen a few of them.
http://www.kensmithbasses.com/doublebasses/uebel/