In general tongue weight should be 7%-10% of the total load (boat fully rigged with gear and fuel, and trailer). Lower than that, and you get that fishtail effect (which is very dangerous).
Dry weight from the Parker site wouldn't give you that number. You would have to add the weight of the engine, fuel, rigging, trailer, etc. Maybe someone with those models will have already calculated the weight of their rigged boat on the trailer from which you could do the calculation.
I've estimated that the weight of my 2510 with twin F-115s, fully fueled and loaded with gear on the trailer is about 8,200 lbs. My tongue weight is now about 600 lbs. She tracks nicely without any sway.
That's a little hard to predict without more information. I'll tell you how to arrive at tongue weight in a minute and you'll see why:
Take the dry weight of the boat, add the weight of the motor, the fuel in the tank at the time, the weight of *all* other things in the boat (fishing gear, coolers, personal possessions, etc.) *and* the weight of the trailer. Add those weights together and tongue weight should be in the range of 5% to 10% of the total, usually leaning closer to 5%. If your rig wants to fishtail, you need to adjust the tongue weight by moving the boat forward or the axle(s) rearward.
Sure, I'm aware of the variables involved in the calculations, but I was kind of hoping that someone had already measured the weight. I used to tow my 21se with a 2003 Ford SuperCrew, but due to rust after a year and a half, and assorted other problems, that thing is gone. But that's a whole other thread ... the vehicle towed great with a fully loaded boat. I'm considering either the current Toyota Tundra or the new one coming out in February. So it's more of a curiosity thing at this point.
Isn't tongue weight also a function of how the boat sits on the trailer. I purchased my 2310 at Norfolk Marine and they did a horrible job of "balancing" the boat on the trailer. We got on the road and had lots of action as the boat sat to far back on the trailer and did not provide enough tongue weight. When I got her home, the first thing I did was move the vertical, (don't know what you call it), forward and that in turn pulled the boat forward on the trailer and gave me the necessary tongue weight. Never had a problem since.
I just got back to this thread and saw that I basically repeated everything you said (is there an echo in here?) - I must have been typing when you posted and I didn't see yours come up in front of me - sorry 'bout that!