Positive line color during clomid cycle

Hello,
    I am new to this forum and I am trying to concieve (conceive) this month on my first clomid cycle.I am on day 16 and just got a + opk this morning. Yesterday  I thought that the line was dark but it was not quite as dark as the test line. My doctor told me that sometimes the line on the opk's during a clomid cycle will not be as dark as usual when o'ing.Has anyone else experienced this?  And if so how dark did the line get? I am using the first response opk. I am taking my bbt this month to find out for sure  when I O just in case this month I get a bfn.
    If anyone is interested I am publicly posting my charts.Take a look and see what you think. Btw I am 43  with ds 9 and ds12. Started going to a new doctor. I have had 3 miscarriages due to low progesterone levels and/or bad eggs.This time I am taking clomid 50mg day3-7 and if I get a bfp I will start progesterone immediately.The last 3 pregnancy's that ended up as miscarriages I never took progesterone.

[tina1111]

My lines have always been very dark with Clomid. I use the cheap opks until I get one that looks positive. Then I use a digi to see if it really is or not. The digis are too $$ for me to use 2x a day, every day. I only use them to verify the cheapos. Usually, a positive Answer brand opk is darker than the control line when positive for me.