Ncik has brought up a good point that is at the heart of the question and the answer. Perfect equality can never be had. Certain make-ups of weather conditions, crews and boats will be favoured in one instance and disadvantaged in others. Even in strict one design classes and classes with elaborate equalization systems it will be that way. The real question is of course how large the differences really are, and whether they are considered to be dominant in the final result. The first is something science can answer and the latter is subject to personal opinion and here we have as many opinions as there are sailors. Some think 1 min difference per hour racing is perfectly acceptable another feels 2 minutes per hour is perfectly acceptable. Only you can make that judgement for yourself.

With regards to your specified weights :

300 lbs (you and wife) = 136 kg
330 lbs (you and friend) = 149 kg
175 lbs (you) = 79 kg

The 136 kg and 79 kg are just perfect; again because they are centred in the competitive weight range as I know it to be. As such there is no way that you can be disadvantaged in any significant sense. Like that you cover both bases (light and strong winds) equally well and in the long run you will always come out on top if your skills are assumed to be perfectly equal to all others.

The 149 kg is indeed higher up in the competitive crew weight range but in my opinion it is still sufficiently inside it. More importantly however the difference between 149 kg and 136 kg is small enough (13 kg) to be using the same optimized mainsail (for 140 kg). I see absolutely no need to have different rigs here.

Many of us race singlehanded with our 2-up mainsails. And that can be done very well in my opinion. But if you are looking for the ultimate competitively, lets say with fully optimized A-cats sailed by skilled skippers (this is a harsh criterium) then yes a special 1-up F16 mainsail will just give you that extra oompf. Is is not different in power but it will just have that little extra drive coming of the bottom of your mainsail together with slightly better accelleration because of the flatter top that twists out superiorly. As such you just pick up a little extra pointing and speed each time a guts comes along or a wave shakes the rig. In perfectly stable conditions the difference will be very small indeed. Just use the same spinnaker.

I don't have too much data on the performance differences between perfectly equal skippers and boats where one is sailing with a 2-up main and the other with a special 1-up main. Mostly they also use different masts and so on. But looking over the data that I do have I'm surprised how small the differences really are. Certainty small enough in my opinion to be far removed from being uncompetitive. And of course it is far more economically attractive to buy a single boat with an additional 1-up mainsail then buying and keeping 2 seperate boats like the F18 and A-cat.

An added advantage could be that if the wind are really honking and your wife is in doubt to go out then you could always throw the 1-up sail on the boat and have it be very calm and relaxed. You don't want to race competitive 2-up like that as you'll loose some speed that way even in very big wind, that I do know, but for recreational sailing and tuesday night club racing it will be fine. And way better then doing the F18 1-up or the A-cat 2-up. And of course getting out on the course always beats staying on shore when your crew says "no thank you" to doing 15+ winds on a F18 with 300 lbs combined. I guess that my point here is that even when things are not perfect they may still be significantly better then the alternatives.

That is the data I have about these boats, but I always end with advicing to just find out for yourself by actually borrowing a boat and racing it in the different configurations. Afterall, only you can pass judgements on what you would consider sufficiently small differences.

I hope this helps you in your research.

Wouter