SHOULD COWDENS PLAN BOTTLES BE EMPTY ON LAST DAY OF MONTH 1?

I mean, ideally, yes. A month's supply should last you a month. Though, I don't think it's impossible for a little extra to have been added to the bottle(s), but that'd depend on just how much is left.

If there's a lot, enough for a few more days, I'd be a little suspicious of whether or not you're hitting the proper dosage.

The angle at which the dropper's held could affect the size of the droplets, yeah. I'm sure it could.

But, either way, I wouldn't get too upset over it, so long as you're still herxing and (hopefully) improving. Just use up what's left, getting as close to however many drops you're on as you can.

*shrugs*

I also read somewhere about droppers - I think it said to hold it at a right angle - and I took that to mean the dropper would be horizontal - but I may not be right. That's how I hold mine. For me it doesn't really matter as long as I am consistent.
I think you could get more if you had the dropper pointing down?