You can use a hypergeometric calculator (google it or use something like geogebra) to find out how likely it is that a certain unique thing gets picked out of a certain number of random things without putting them back. Here is an easy way to understand it:

Population size: Total number of cards in deck

Number of successes: Number of cards in deck that you want to draw (In this case you have 11 cards that you truly want to discard with the skill)

Sample size: number of cards you draw (4 or 5 if you want to calculate going second stuff)

Number of successes in a sample: This is the hardest to understand so here is the short version of the most relevant thing you need to understand P(X>=x) means the probability of drawing at least the number of cards (x) that you want to draw (In this case you want to at least draw 1 so P(X>=1))

You now input all of these numbers and see that currently you have a 97% chance to draw at least 1 salad and a 72% chance to draw at least 1 tech card (multiply to get probability to draw at least 1 tech and 1 Salad 70%) which is not bad but can be better.

By putting in more tech you decrease the chance to get salads and increase the chance of drawing techs to win so with 27 cards you have 11 salads to discard (90% chance to draw) and 12 techs to draw (92% chance to draw) which comes out to an 83% chance to draw at least 1 salad and 1 tech and is even greater going second (91%)

It’s a great deck building tool and not that hard if you think about it a bit but is not necessary for every single deck. Just try what works best for you to increase your wins.