All of this is excellent feedback, it will definitely be a MASSIVE undertaking but don't be daunted by numbers that Howard is throwing out there. They are true- these projects are a time vacuum, but you don't necessarily need to commit to those quantities of time. I did at the start, but I experienced all sorts of highs and lows going through my build, and sometimes the best thing for me to do was not see it for a couple of months. If you know you can't put that time commitment together up front, don't let that stop you from moving forward. Things will come up during the build. I had an interstate move for work, a house remodel, a 3 month sabbatical, a wedding... All sorts of things come up. Backing down the commitment will drive out the completion date, but if you're not doing this professionally, it's all part of the process of building a car. For a reference, it took me 5 years (I think) to get mine moving and registered. Notice I did not say "finished".
One thing I have seen very helpful if you do decide to jump in, the easiest way to log time is to commit to doing something on the car every day. It can be just a 10 minute job, but do something which puts the car in front of you and you touching something which goes on or into it. If you do that, you'll have no trouble logging the hours. One small thing turns into a couple of them, because hey- you're already in the garage anyway right? Before you realize it, at least an hour has gone by and your wife is wondering where you are.
The old adage of eating the elephant applies here. One spoonful at a time.