Re: Electrical - wiring Question
The second drawing looks like it. The instructions say there is a cover plate included to fill the hole when the plug is removed.
The first drawing is also correct, except it shows the plug pin "Y" screw being used as the tie point between the shoreline and the meter. DON'T DO THIS AS PICTURED! Leave the plug pin un-connected, and use a wire nut to joint the two wires inside the box. If you use the male pin as a tie point, there would be hot 110 volts for someone to poke their finger into if the inverter was unplugged and the shoreline feed was live. I think you were just using this as a convenient place to modify the drawing, yes? I don't see any problem with either plan with this correction.
One thing to consider when using a 220-volt panel on 110 volts, is that every other breaker will be dead in a simple install like drawing #2. There are two 'hot' bars in the back of the box, one for all the odd numbered ('A') breaker positions, and one for all the even ('B') ones. One side of the double main powers each bar. In drawing #2, all the even 'B' circuit breakers will be dead.
If there are already more breakers on the odd bar than you need, then just use them and ignore the even ones.
If you need more breakers, there may be lugs on the ends of the bars not shown in the drawing, to be used as power inputs in some other configuration of the box. If this is the case, loop a jumper of #10 or larger wire between the two lugs to power the second bar from the first bar and thus power all the breakers.
If there are no lugs, and you connect the feed from the meter to both poles of a double main, then you could draw 30 amps on the 'A' side and 30 amps on the 'B' side before it trips. Even if the shoreline and the lead-in can handle it, you are drawing up to 60 amps through the 30 amp meter. Not a good thing. Using a dual 15 will protect the shoreline and meter, but will cripple how much you can draw from each pole.
Breaker 6A/6B looks like a double pole 20-amp unit. If you jumper the two outputs and turn it on, you would have four branch circuits: 4A, 4B, 5A, and 5B. 4B abd 5B together would have to draw less than 20 amps. I think you were thinking about 4 circuits, so this may work. Another option is to replace the full-size breakers with half-width ones, but why buy all new breakers if you already have them?
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.