i think that it will need a lot of trial and error to find what works for you, start with 10 minutes if you feel like you need more time to think add more time, if you think 10 minutes is too long then maybe change it to 7.
Daily Game Time Management
With choice 2, you might be exposed to more positions, but if you use a superficial thought process during your games and don't analyze them afterwards, you aren't gaining the benefit of playing more games. When thinking about a position, there are times where minutes can be spent and there are moments where it is beneficial to spend much longer. I wouldn't set a limit to how much time you spend on a position.

Bullet is completely useless for people who wishes to improve. For novice players blitz is almost completely useless as well (compared to longer games).
@OP
Daily chess is ok for some improvement, but it is a different form of chess. It is easier in a sense that you have opening explorer inside the game itself and you have analysis board where you can make moves for you and opponent to help you decide on a move and because of this you do not train your visualization.
The best improvement wise is to play longer rapid games - 15|10 games or longer if you have the time.

I have zero interest in bullet and blitz. The shortest time I play is 15|10. I wish I had time to play longer games, but I rarely do.

I have zero interest in bullet and blitz. The shortest time I play is 15|10. I wish I had time to play longer games, but I rarely do.
15|10 is already ok for improving your game. Of course it is still a bit different when compared to long games like 45|45 or 1 hour per side (I enjoy those the most), but you will have time to think. After you play it, try to go through it and figure out where were the mistakes and if you could improve upon it somewhere.
In the beginning, you will probably only notice really bad moves, but as long as you learn a single thing from the game at least it is beneficial.
I would join a tournament so you get about 10 games at once, If you go with option 1 be aware you can lose a lot of rating points if you lose just a single game.

I would join a tournament so you get about 10 games at once, If you go with option 1 be aware you can lose a lot of rating points if you lose just a single game.
i think the op is more concerned about playing games and feeling good about how he played than rating
I do agree with tournament though you get little bit of both
and I would say stick to 10 min per move no more
I've been advised to focus on daily games (as opposed to rapid games) to improve, as daily games allow ample time to think about the position and your next move.
Which do you all think is better for improvement:
1) Have a small number of daily games running (say 2 or 3), and take as much time as you can on each move.
or
2) Have a larger number of daily games running, and take less time per move/game.
1) has the advantage of giving you more time to think through the position. But 2) exposes you to more positions... I've been using 1) lately, but I find myself spending so much time looking at a position, going through the same possible moves over and over again... I might be wasting a lot of time for nothing. Do you think it's better to set a time limit on how long to think about a move (I don't know what the limit would be. Let's say 10 minutes)?