I hope all is well. I am not too familiar with the Tartan 42. Very good reputations, of course. Sail well. Is the hull solid or cored? I would not get a cored boat over 20 years old.
Galley on the Hood 38 was the only disappointment, but, no boat is optimal. Loved everything else. especially the roomy forward berth...most important.
Does the T42 have a separate shower? That would be a plus.
Forgive me if I forgot, but do you have a sailing companion? If so....really depends on what she thinks. If not...then give stronger consideration to the Hood 38. One thing I found...I could sail my boat anywhere, anytime, solo. My good friend experienced sailor on his Whitby 42 never went anywhere, because he could never find crew to make anything more than a day trip, and he would never take a 42 out for a day.
You should negotiate a very good price on a MK I. They are not in demand.
I *think* the tartan has the same style companionway?
I hope this message reaches you. It has been about three years, since I sold Invictus. And I still think this is one of the best designs and builds ever. Newer designs might be easier to keep clean (because of the all plastic, molded, all round edges heads and galley's) but, I would think the price on the 80's era W38's makes them a great value.
I really liked having two private staterooms. No boat has the space of the 1BR condo...so....gaining any privacy at all is a big plus IMHO.
Not sure of the calculation you are referring to. The ballast to displacement ratio is 50% on all the versions.
With any boat of this age, be sure you check carefully for blisters, or make sure a blister job was documented....and get those documents.
Hope this helps, and best of luck.