>Re "justifiable": I recommend looking at that from the point of view of your former employer and potential client. To them the value of the work you would do could be many times your hourly rate, so the difference between $70 and $100 is negligible. Since you were formerly employed by them, you should have some insight.
>
>As an extreme example, my first job after university was as a process engineer with a large manufacturing company. They had a production line that ran 3 shifts (24/7) with the value of line time about $10,000 per hour.
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>One day they'd been running for about half a shift and all the product was failing in QC. The shift supervisor, production manager, and my immediate boss were all at the end of the line, scratching their heads, trying to figure out what was wrong.
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>My area of responsibility and knowledge was the start of the line, I knew nothing about the end of the line and packaging processes. I went to see my boss about some other matter. I wondered why everyone was at the end of the line and they explained what was happening. With "fresh eyes" on the problem I had a flash of insight. Based on that we made a "crazy" adjustment to the line configuration, and within 5 minutes the product was passing QC with flying colours.
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>Looking back on it now, those 5 minutes paid my salary for the entire year.
>

It's great to be able to recall those insights, isn't it? For me, they make this profession sizzle.

Here's some irony - for about 25 years, I commuted to NYC from Long Island -sometimes by train, sometimes by car - at least an hour in each direction -all that time was off the clock- but I had some of my best ideas during those hours and wasn't paid a nickel for them.