Big And Tall Catalog Help Needed On Choice Of This Item While Internet Shopping For Clothes...?

Help needed on choice of this item while internet shopping for clothes...? - big and tall catalog

When I get what I had. I mean, I'm not stupid, but says big and too heavy for what that means exactly that. If I do that for me it would be this t-shirt is too long and touch my knees or something. I am thin and 5 '11. "Please, what do you think? Useful observations:

http://www1.macys.com/catalog/product/index.ognc?ID=237447&CategoryID=24710