Initially I wanted to choose Eldritch Immersion because holy shit 10,000 to 20,000 XP and immediately getting level 4 Eldritch would be awesome. Plus there was the initial desire not to simp even if I support a Penny and Sol ship. Then I saw Birdsei make several posts on Discord and I started to lean towards Angelic Immersion. But I decided to sleep on it.
So the main three options I considered where Storage, Eldritch Immersion, and Angelic Immersion.
Storage seems to have a lot of potential because we could potentially absorb it but more efficiently, make an Artifact out of it or spread it throughout the whole class. But the main downside is that we will need to keep the Eldritch Flask safe on the journey back and secure it until we do something with it, we frankly don't have the security to keep it safe and the trip may require us to have the power up.
Eldritch Immersion comes with a lot of benefits primarily making Sol really strong and the strongest first year. Like even at the lowest levels of it he will be physically equal to Harrison that's without even spending that much XP only getting Eldritch to Level 5. This will make him safe from the Tarot Class and make it a lot harder to for the Upperclassmen to push Sol around. This will also free up Sol's actions economy to do stuff like focus on socializing, possibly recruiting minions, resting and doing remedial classes.
Being the strongest can be a double edged sword. People are already taking a notice of Sol because of him going to Remedial Classes, becoming the strongest Enrolled in our year will only confirm the fears about Sol's potential which will bring even more heat on him from the upperclassmen even if he'll be able to handle it. There's also the presumed obligation that Sol will need to fix the Tarot Class's shit.
Then there is the much longer term to consider, this will help in putting Sol on the path of graduating early, help him prepare for the Lamb, and give him enough power and time to identify the at minimum 6 hidden modifiers on his character sheet. Strength will not only be useful in defending Sol against threats and boosting him but also in preparing for the crazier shit he'll get into down the line.
Angelic Immersion is something that will massively benefit Penny with only a little direct benefit to Sol in the form of getting 3 pluses with Penny and getting a measly 250 XP. Penny will get 15,000-30,000 XP, Seraph to level 4 immediately and become the strongest First Year.
It seems to have little to benefit to Sol at the first glance but there are several positive things from this choice. First and foremost is that we can get someone else to deal with the Tarot Class's messes and have the class be more unified under a leader, while not having that leader be Sol which is basically how you are supposed to play Sol according to Birdsie. It also places the strongest First Year on Penny so Sol doesn't have to deal with. There is also the fact that after this Penny will become a XP and Will booster for Sol because she wants to repay Sol.
But there's also the downside of this whole thing empowering Penny instead of Sol. Sure Sol will get a lot of XP out of this trip and will get a boost but it's pocket change compared to this.
The fact that we will be getting closer to Penny is something to consider (At the cost of simping). Penny is one of the Enrolled with the most potential given she was a possible character choice, she is in charge of the Explorer's Club which has a lot of power, her parents are some of the strongest Enrolled around and have connections to other Enrolled.
But this comes with the negative of hard locking us into being associated with Penny. Penny has moral standards that Sol can respect but will still have to deal with. We will be forced to join the Exploration Club which while many people want to do already would take away some of the player's freedom. Penny's family has so much baggage and drama, it isn't even funny and Sol will be tangentially aligned with them through Penny.
So for me the two options are between the Immersions. Eldritch Immersion and Angelic Immersion both have their costs and benefits and will dictate how we are going to play for a good long while. But both are valid ways of doing things the question is what do I want Sol to do?
Dual Immersion is the best option though since it has the most overall benefit from both people and makes it so that the Tarot Class has two heavyweights.
There are two things I want Sol to really do on this quest, for him to break free of his despair and to untie the Tarot Class or at least a large part of it. Sol moving beyond his despair will be good for him both as a person and a way for him to get a lot more Will. Uniting the Tarot Class is useful because it's one of the classes with the most potential synergy and we could make make it into a very potent faction. We've seen how having a united Class can be extremely beneficial to an individual and class as a whole, just see Meta and the Mars class.
[X] Dual Immersion [30 Will, 12 Credit] - Effort is a most scarce quiddity.
The best choice is clearly this because it's pretty much the immersion option for Distribution.