I would like to say that I'm a relatively fast worker who always finished SAC's at least half an hour before time is up and still had to guess the last few questions. However, I did not do practice questions under timed conditions so that could have effected my performance during the UMAT. My time management was almost perfect being behind at half time by only a few questions so I would say it's possible with a little practice although how much practice is impossible to determine. A few of my friends did the UMAT and they didn't even finish despite guessing as many questions in the last few minutes and they studied for the UMAT way more than me.
If I were to re-sit the UMAT, I would first skim over every question during reading time and skip the questions that I know would take time and write the number down on the answer sheet to come back to later on. I personally found the pattern questions easy so I did those as fast and precise as possible leaving time for what I found difficult; the non-verbal reasoning. After doing some practice questions, you start to see a pattern to most of the questions so don't let my experiences get you down. I'm sure you'll do fine! I wish you all the best and good luck!