first day clomid all at once?

I received my delivery of liquid nolvadex along with liquid clomid today and plan to start my PCT for my 4 week 20mg ED M1T cycle. I am curious if I can take all 300mg of the clomid all at once or I have to space it out more than once throughout the day. If possible Id like to take the 300mg of clomid and 40mg nolvadex all at once but I wanna be posative this is correct.

You could do it all at once, but im not sure how long the half life of those compounds are. So why not just space out the doses to be careful.