A few years back when i was single and looking for a shidduch – not knowing about this segula i though to myself that i know purim is like yom kippurim and therefore i should spend the day better than i usually do. So purim night, instead of going out driving with friends and watching all the rubbish people get up to i stayed at home and really davened hard, i davened maariv with alot of kavana, i then started on the tehillim. I didnt finish it before the next megilla reading, but the next morning i spent the morning davening with alot of kavanna and carrying on with tehillim. It took me over the whole day to say the whole tehillim as i still had to go out give shlach manos etc but i didnt waste my time like i had done the previous few years, and that year i got engaged.
Secondly, i know someone who had a number of daughters in shidduchim – the oldest being about 24, then 23 then a boy of 22 and another girl of 20…or something along those lines, and things just weren’t moving. She’s a busy mother of many kids, but she took the time throughout the day to try and finish the sefer tehillim, and she finished it just before shkiya on purim day – her 2 oldest daughters got engaged recently a month apart bh – so for all those who want to use this segula – i’m sure it’s a segula to try and finish the tehillim in between the 2 megilla readings, but at the end of the day it’s our tefillos that Hashem wants, and if we show Hashem that we’re trying our best to daven as much as we can even though it’s such a busy day and we make time for Him – i’m sure He’ll listen even if we dont manage within that short time frame.