Most people won't answer this question simply because this would ruin/reveal their easy TC profit, but since I know the method and I'm not doing/selling it, I have no problem to explain.
Here is the explanation also for those who don't know how they obtain the items needed for the full 300 points:
They create makers (level 8 character) and ask the City Guide to escort them to Oramond Depot, then they clear the way (they probably trap creatures) with their main, so their makers can go safely to the NPC that gives the task "Probing". They get containers with low oz (Present Box is the best considering it weighs only 5 oz), ask for the task to the NPC Doubleday to get 1 item, move the container with the item to the ground or to the closest storage and wait 30 minutes to ask the item again. The mechanic works like Rashid's mission where you can't move the fine vase or else it will break. But you need 300 of those probes because every task is worth 1 point, but with 300 items you can do one task and get 300 points in one go!
An example of storing the items:
300 present boxes with 1 probe each
They move the box out of their backpack and repeat the process every 30 minutes (NPC cooldown for lost item).
The questlog would look like this (each point is counted as if you did the task 1 time):
Probing progress (1/1) -> (300/1)
That depends on the sellers, but what most of them do is sell the points and clear the way (because some of the monsters on the way are the Fungi from Warzone) so you can use all the points with the seller's help and don't risk losing the probes. That way all you need to do is click one button every time he puts a probe on the ground, meaning you will need to use it 300 times.
Here is a video in Portuguese-BR that explains and show how the method works. Maybe you won't understand the language, but you can have an idea:
https://www.youtube.com/watch?v=c0l3XZDOPxs&ab_channel=TibiaCapotao
Also here it is the quest on Wikia if you have more questions on the full Quest:
https://tibia.fandom.com/wiki/Oramond_Quest/Spoiler#Probing
Good luck!