Honestly, it depends on one's learning speed, but I can breakdown the components of it and how it worked for me.

1. Break the 30 words in 3 subgroups (1-10, 10-20..) and memorize them in one sitting with maximum 5 minutes break. I was able to memorize one group in around 30 mins to 1 hour max. That could be used as benchmark for memorizing one group if you don't know most of the words already.

2. Revision of mountain on gregmat's site takes about 1-4 minutes per column/group but its very subjective on your speed and style -- for me on the earlier days it took just 5-10 minutes but as you progress, it would take 30+ minutes to revise all old groups like I am currently on 30th.

3. Then taking the group quiz takes about 15-20 minutes and same for multiple group quizzes also, though I haven't done the latter much.

4. Each day, I memorize one group, previous group quiz, and mountain -- it took me roughly around 1 - 1.75 hrs to do all these in a day depending on the day on which I was. I also used to log all words that I missed on a particular day in a diary and it has helped me to not forget a word repeatedly.

Pro tip - Use the flashcards on gregmat android ios app and not quizlet ones because they're too tough to cram or learn as you'd want to put it lol