Deck stain for deck with tight boards

Hello - 

I have my deck just about all prepped and ready for stain.  I have one rail left to sand/paint, then plan on sanding the boards before staining.  I'm on the fence whether or not to use a cleaner/brightener for the boards...I've already power washed them.  Figure I'll see how they look after sanding. 

Tthe boards are very close with no gaps to let water through, so it just pools up.  I've tried to use a circular saw to create a gap, but once it rains again they have just swelled again.  Especially recently with Florence.  I'm in central NC.  So I'm thinking I just need to put the best stain down and go with it.

What would you recommend? Sawing/trying to put stain in-between the boards?  Or just sand the boards and put down stain?

Also, I'm trying to decide between the RAD, Defy Extreme, or something like Olympic Max from HD.  What would you recommend in this situation? 

(light walnut is the color I'm leaning towards)

Thanks!