I recently went through the Simon-Kucher online test for the LATAM-office and it´s pretty much a SHL-style test (look it up online), which is not difficult at all.
There´s an exercising part (about 8 questions) before you start so you´ll get familiar with the type of questions they are asking and you can pause after this exercising part, you don´t need to directly continue with the actual test.
The actual test contained 18 questions pertaining to 3 main section/parts:
First part: Graphs displaying the revenues and profits of different branches of a company and they might ask you about the share of the renewable energy devision among the total profits, etc. Pretty chilled.
Second part: The second part addressed the allocation of hours within different business units of a company and compared the ratio and allocation of these hours. Again, pretty chilled
Third part : Pretty much a currency calculating part: They will display you the exchange rates of three different currencies and might ask you about a conversion of dollars into Bhutanese Ngultrum. Sounds scary, but again, it´s pretty chilled
Fun fact: Deloitte Switzerland provided me with the very same test, so its mor of a general testing rather than a specific test made by Simon-Kucher.
In total the testing consists of 18 questions within 30 minutes, trust me, time won´t be the critical factor.
Hope this is helpful for you and good luck!