Using FMU with IC OPKs?

[GingerbreadHead]

How's that for a bunch of acronyms !
I know technically you shouldn't use FMU with the cheap OPKs, but I was wondering if I used them every morning throughout my cycle with FMU would I see a line progressively getting stronger as I got closer to ovulation, or would the results just be totally invalid? Probably a daft question, but I am struggling to not go to the toilet for 4 hours every day, and making sure I try and use the OPK at the same time every day.
Any insights or information much appreciated!

I think afternoon is supposed to be better because there is a hormone surge in the morning which can give misleading results.

I never bothered waiting 4 hrs, more like 2+ish and didn't drink loads beforehand, and I usually got clear results.

I usually do mine around 10.30am, sometimes the last time I've gone to the loo before then is 9am and I still get a good reading, but I do make sure I don't drink anything before apart from one cup of coffee first thing.