Dana, Dhamma Talk or Retreat

Dana, generosity, is considered the first of the 10 perfections (paramitas). A very comprehensive text about dana can be found here.

A sutta underlining the potential of dana: MN 142

There are these fourteen offerings to an individual. What fourteen? [...]

1. Here, Ānanda, having given a gift to an animal a hundred-fold offering is to be expected (in return),

2. having given a gift to an unvirtuous ordinary person a thousand-fold offering is to be expected (in return),

3. having given a gift to a virtuous ordinary person a hundred-thousand-fold offering is to be expected (in return),

4. having given a gift to an outsider who is without passion for sensual desires a hundred-thousand times a hundred-thousand-fold offering is to be expected (in return),

5. having given a gift to one who has entered upon the way to experiencing the fruit of Stream-Entry an immeasurable, unlimited offering is to be expected (in return).

6. What to say about a Stream-Enterer?

7. What to say about one who has entered upon the way to experiencing the fruit of Once-Returning?

8. What to say about a Once-Returner?

9. What to say about one who has entered upon the way to experiencing the fruit of Non-Returning?

10. What to say about a Non-Returner?

11. What to say about one who has entered upon the way to experiencing the fruit of Worthiness?

12. What to say about a Worthy One?

13. What to say about an Independent Sambuddha?

14. What to say about a Realised One, a Worthy One, a Perfect Sambuddha?

While dana mostly seems to fall under the training of morality, practicing the dhamma and listening to dhamma would be more on the side of concentration and wisdom. These three aspects, the cultivation of morality, concentration and wisdom sum up the Noble Eightfold Path. So practicing as much as you can according to this path in any way is the best choice.

Dana has more power than many people think. From Giving Sutta

Then there is the case of a person who gives a gift not seeking his own profit, not with a mind attached [to the reward], not seeking to store up for himself, nor [with the thought], ‘I’ll enjoy this after death....—but with the thought, ‘This is an ornament for the mind,(cit­tā­laṅkā­ra­citta­parik­khā­raṃ) a support for the mind’—on the break-up of the body, after death, he reappears in the company of Brahma’s Retinue. Then, having exhausted that action, that power, that status, that sovereignty, he is a non-returner.

I tried to find where else Buddha used "ornament of mind" to clearify the meaning but I couldn't find anything. So I searched what type of people who would be reborn in Brahma's world and after that, a non-returner. I found out that The noble disciple who are expert in entering any Jhanas or arupa sanna, like (take pleasure in, satisfy) in that state, and maintain such ability by time of death (not exactly as dying in that state) they would enter Brahma's world according to his meditation level reach final nirvana after that.

this is strictly my conclusion: one of the characteristics of Jhana is abandoning five hindrances, and maintaining perception in giving, (Danna sanna) can also do the same as medition.

So IMO, giving as ornament of mind = perception of charity or giving in such a way that it abandons 5 hindrances of mind.

noble disciples are stream enterers or higher.

Merits, through ‘Daana’, ‘Sila’ & ‘Bhavana’ bring you joy. But Bhavana (Meditation) is not so important at the start. So leave the retreats for a later date. As the Buddha preached:

“Don’t ignore even a small merit thinking that it will not come to you! It is in fact with each drop of water that a pot is filled. Therefore, a wise person will collect all merits even if it is by bit by bit. In this way, his life will full with merits at the end.”

It is important to know that no degree of generosity can cover up the lack of virtue in personal life. This karmic law cannot be deceived. This is why it has been laid down that "give dana with confidence and always be virtuous" (daanam dadantu saddhaaya - seelam rakkhantu sabbadaa). The two aspects should be complementary to each other.

So cultivate the five ‘Sēkha Bala Dhamma’ – Saddhā (faith), Sīla (virtue), Sutha (Dhamma knowledge), Thyāga (generosity), and Paññā (wisdom of the Dhamma). Also religiously go through the stages of listening, remembering, constant reciting, mental observation and ideologically understanding the Dhamma (Sutha, dhata, vacasa paricita, manasanupekkhita, ditthiya suppatividdha). An interesting fact that very few know of is, nowhere in the Doctrine (Sutta) it is mentioned that one becomes a stream entrant (Sotapanna) through meditation. So to your next question, listening to dhamma is more important than practicing meditation. Meditation comes only when one strives to go beyond the stage of Sotapanna.