Agree with your probation statement completely. As a for instance, lets say that you are within 2.5 hours of LAX, but not SNA. I'd say you were completely safe showing at 1-2 hours later, depending on traffic, due to SNA's further proximity with no cause for concern. There's no way on earth the company can expect you to hit a moving target when on reserve and I do believe past practice used to be you get there when you get there.

SFO based pilots are paid "in the rears".

The rest of us are paid "in arrears".

Technically, the check on the 1st is for 1/2 of your monthly guarantee. For lineholders this is 35 hours, but since reserve MMG is 73 hours, their 1st-of-the-month check is 36.5 hours.
Also, if a reserve didn't break guarantee then the 16th of the month check might not be much larger than that of the 1st.

I've been both a line holder and reserve and I can say with 100% certainty that my paycheck on the 1st has always been 35 hours. I know the part where you are talking about 1/2 your guarantee...but I've NEVER seen it done that way.

Now THAT's funny right there....don't care who you are!

What's the latest with Open time? Is it easy to get and are there benefits for newbies to pick it up? Is taking open time out if base a possibility?

Depends on the fleet and base. Small bases get way less open time. Large bases get a lot more.
For instance. EWR or ORD 737 gets a lot of open time. On and off reserve you are welcome to pick up trips to your heart's content.

If you are EWR based, can you pick up open time in DEN?

I've been online since Jan, and there has always been opentime trips to pick up if I wanted to. EWR base that is....

Yes but not until 1300 the day prior and they won't drop trips on your line to accommodate.

If you want to make more money, Senior Man and sit at home. Wait for the company to call you at 200%. Everyone in EWR got that... Other bases not so much. Nothing more disappointing than seeing 20 pages of open time pick up requests.