The Aries Helene uses 2 banks of Analog Devices AD1865 NK chips which can process up to 18-bit/96KHz. If your musical source is 16/44.1 CD then you are fine, but if you feed the Helene a high-rez 24 or 32-bit file, you'd have to dither that signal down to 18 bits or the DAC will truncate it down to 18 bits. I'm certain of this because my DAC uses the same chip.
The Mola Mola Tambaqui is a more modern design. The description seems to indicate that it can accept up to 24/192 via the USB input and 32/384 via the other inputs. It also will upsample all inputs to 32/3.125MHz. No truncating in this design.
Again, I haven't had the opportunity to listen to either one. I'm not saying that your decision should be based only on the bit-rate you're trying to play, but it may matter, especially if you have a lot of higher bit-rate recordings. I'm very interested in both designs, and I'd like to hear both.
What is your musical source?
Dave