Dipsticks only measure the amount of oil in the bottom of the oil pan. You shouldnt check the oil level when the engine is running because oil gets sloshed around in the bottom and on to the dipstick unevenly. my guess is that you could run the truck for a short amount of time but you would have to watch the oil pressure and make shure the leak doesnt get out of control because it will leak some. but doing that is like walking on thin ice. If you get an oil fire you are done. I wouldn't try it.
Since the tube attaches to the oil pan, you will probably loose oil out the hole in the pan. that is if I understand you right in what you are asking. You can get a whole new tube and stick fron Jeff's bronco Grav eyard for about $40.00.
Yes, you will lose one quart per 100 miles without the dipstick tube in place. Some go into the oil pan, other models go into the block. Either way. a hole that size (5/16") will flow a good bit of oil.