A few things here.
BOINC time estimation. BOINC is generally not that good at estimating run times on tasks. If you're at 17% after 9 hours then there is no way that 52 days remaining is an accurate measurement. There is nothing to be done with that number except ignore it. If you're at 20% after 10 hours (for example) then the task should take 50 hours total and not 50 days.
Storing one day of work. That setting generally doesn't work as intended because of BOINC being bad at time estimates. There is also the issue of some projects here that take longer than 24 hours to run even on modern, higher end, hardware.
The general advice here is to keep 0 cache (store 0 days of work) so that you are only downloading tasks as the previous task finishes. If you have a reason to store additional tasks, such as intermittent internet access, then you might want to store some additional work. You can play with the number to best suit your needs.
This setting has no bearing over how long as task takes to run. It only affects how many tasks you have waiting to run. This can, and sometimes does, store way more than one day worth of work.
Project selection. There are a variety of different task types you can run here. These tasks have run times that range from a few minutes per task to a few days per task depending on your hardware. From your main account page you can go to PrimeGrid Preferences and select which types of tasks you want to run. By each task type you can see average run times to get an idea for what you can expect to take time-wise to run a task and then select ones more to your liking.
Deadlines. There are variable deadlines here. BOINC doesn't know that, but as long as your computer is working on a task then there's no problem. You can see the deadline for each task type on your PrimeGrid preferences page. The deadline for the type of task you're asking about is "Deadline: 21 days (up to 84 days)". So even if your computer did take 52 days it would still arrive ahead of the deadline. BOINC would be unaware of the deadline beyond 21 days, but it would continue to work on the task until completion.
I hope this helps.
Badge Score: 2*1 + 4*2 + 6*12 + 7*1 + 9*2 + 10*1 = 117