Thanks, Boris, for that detailed workup.
The TomCats have more room and I think that extra room seems to accumulate stuff. Also, 150 gallons of fuel, electronics modules, ditch bag, bbq, gas grill, pot and pan set, canned food, microwave, television, DVD player, extra batteries, emerg. oar, hoses, fenders, poles, tools, spare parts, a/c, genset, extra lines, spare anchor, etc.
Another consideration is that, as long as you don't overdo it and as long as you are not out for speed, the heavier laden boats ride more smoothly and steadily.
It all adds up.
John