mommasboy,
I'm 6'7" and about 285-300 (depending on what's for dinner). I have been bow hunting for over 35 years. The Summit Goliath is the best climber for a big person that I have ever used, bar none! It's solid with plenty of room. I tried a friends Lone Wolf sit and climb, the stand is very solid and quiet but lacks the room for larger hunters. Each year I ask Andre at Harrisburg to make a bigger model, but no luck so far.
As far as lock on type stands, I use several types. The Lone Wolf alpha lock on is excellent, get the tall seat height option. The Non Typical Outfitter lock on type is also another of my favorites. Of course I still hang my 3 Screaming eagles each year, they are over 18 years old and still solid as a rock once set up. This year I am definently going to buy one of the Chippewa Wedge lock stands, the Brutus maximus. I saw it at Harrisburg and after sitting on it and even hanging it on the make shift tree that they had at the booth I was realy impressed. The instructional video that they gave out on this line of stands is also very informative.
Good luck and don't settle for a cheaper stand, the security of that larger stand is well worth the extra couple dollars especially for normal sized people like us.

bmott