Non-profit restricted funds - best way to handle

I recently created my first non-profit.  I watched a lot of videos at the before setting it up and decided to use classes for my three main reporting buckets for the 990: Fundraising, Programs, and Administration.  This is working fine; however, I'm not using them for my deposits because those categories only make sense for expenses, but now I'm not sure that is correct.

The other issue is restricted funds, which I only have one of them so far.  After my research I planned to use Projects in QB Online to track restricted funds, but am now second guessing that because I read it's best to use classes.  The other option for restricted funds (to track both income and expenses) is to create subaccounts to the bank account for each one.  Which of these options would be the easiest/cleanest for someone just starting out to use going forward?  I don't expect to have too many restricted funds, but of course you never know.  

Also, if you believe I should use classes for restricted funds, I guess it's not too late to change that.  However, I understand there is a limit of only 40 classes in QB Online Plus and I didn't want to reach the limit and have problems in the future.  

Thank you for any insight on these issues!