I doubled up on OPKs this cycle too.
I used only ICs last month and never got a strong positive so really wasn’t sure what was going on. So this month I bought a Boots packet and started the day or so after AF ended (CD7 I think).
I did a Boots one in the middle of the day around 1pm, and I saved up pee beforehand (didn’t pee after 9am). Then I did an IC around 7pm. My ICs did show lines around the time that I got the strong positive with a Boots test, but according to their instructions that is still a negative!
I’m really glad I did because I got a strong positive on CD11, a good few days earlier than I would have expected.
If I don’t get a bfp this cycle I’m going to do the same and double up next cycle.