As Joel said, we all have our opinions, and at least mine are worth what you pay for them... so here are mine:
This is not an important option in my thinking. Take good care of one, and you'll not have problems. There are always ways to get an anchor up without the windlass. They might not be much fun, but it can be done. The extra weight DOES matter up on the very end of the boat. And it is not just the weight of the windlass, but the weight of the second anchor moved out to live full time on the roller, and its chain now always lives in the chainlocker. Using two anchors at once certainly does happen, but not often unless you are cruising full time in the Bahamas, even then it is onlynsomething like 10 or 20% of the places you'll drop the hook.
More is better--always. The old joke, "How much much money does it take to go cruising? All you have!" is doubly true of power usage. People who installed 400 watts of solar are likely to say that that it the right amount, people who installed 300 (or 500) will say the same. I doubt you will ever run into anybody who wishes they had installed less! We put 600W of high efficiency panels on an arch because that was all we could fit. If there was an easy, attractive, and safe way to rig 800W, I'd do it. Our 600W panels supply the boat, but not us.
Here is what I mean: If we are plugged into shore power I will typically turn off the battery charger and just let the panels top off the batteries every day while our AC needs are met from shore power. The panels just keep up with our two refrigerators, one freezer, cabin lights and other miscellaneous DC power needs.
If we are at anchor, our personnel power use for electronics and other small uses just overtop the panels supplies most day and we need to run the generator a little each early morning, which is when we run the watermaker. Less the watermaker--our overall use of DC power at anchor is about 1.8 to 2.5 kW-hrs per day
If you are crossing oceans, two autopilots is barely enough. They work great--until they don't. Do as Joel Potter suggests (always a good idea!) They are complex electro-mechanical devices and failure is not just an option, it is to be expected. Hand steering with a short handed crew on a long passage is not fun.
Bill Rouse's number of an autopilot failure one in ten passages would lead to an expectation that both would fail in one out of 100 passages. I once sailed 800 ocean miles without an autopilot. I would really, REALLY prefer to never do THAT again.
Don't let anybody tell you how long is right for YOU. It is like someone trying to tell me I should like Brussels Sprouts because they taste so good and EVERYBODY loves them! One one end, I know of someone who set out on a circumnavigation and 20 years later had not left the Pacific Basin. I know someone else who circumnavigated in 18 months stopping only for provisions and repairs. One thing they had in common: They both did exactly what was right for THEM and had fun doing it.
Providenciales, Turks and Caicos Islands
I am so grateful for all the responses!
We sailed this past weekend on what we hope will be our new Amel 54. Loved it. What an adventure machine!
Thank you guys for your thoughtful and complete responses. I have no doubts nor does my beloved that we're making the right choice.
I do have a few other questions if you would bear them:
One windlass or 2?
How much solar is enough, how much too much? Is there ever too much?
Is one autopilot enough or is a backup the way to go?
The plan is a 4 year circumnavigation. Maybe 7? Maybe 2.
You guys are such a great crew and I really appreciate it.