This is somewhat related to artifact 2266335.
It would be ideal to imitate this option after the way it is handled in Thunar. If you check "Open files with single click" then a slider becomes available below it allowing you to fine tune the amount of time it takes for a selection to occur due to hovering the cursor over an item with an option to disable the selection feature if the slider is to the far left.
Due to the undesirable changes to Nautilus and my dislike of the lack of tabs in Thunar, I've found myself hunting for a new file manager and found myself really enjoying PCManFM besides for this one little limitation. I hope something can be done about this, I really prefer single click activation, but I would like a chance to adjust the speed of the related hover select feature.