Never use FRR, it takes forever to actually lend out anything.
Nope. It highly depends on the time frame - if you use 2-3 days that might be true, but then again if you are using FRR you don't have to care about short term rate spikes anyways.
How fast is it when doing 30 days FRR? There seems to be a gigantic wall of offers anyway.
It's not any quicker to get lent out using 30 days as you're in the same queue. But if you manage to get lent out at FRR using 30 days means you have a good chance to stay lent out for some time and then the interest you receive is variable ie. goes up and down with the FRR. I found it quite good to use 30 day FRR when there aren't many offers and you can get filled easily, the problem is that most of the time that isn't the case. Then someone returns the loan early and you have to log back in change it to a rate that will get lent out. After a couple of months of trying, I decided that automation was essential to making the most income.