Stem sizes can be tricky. Keep the stem from your original bike just in case the substitute stem doesn't work. As for recommendations, get what you like. I have a ton of bars and would sell them cheap, but the shipping costs about as much as buying a whole bike at a thrift shop. My mom had an old Schwinn Continental and I switched the drop handles on her bike to upright handlebars from an old three-speed. This is nothing new or brilliant. The Schwinn Collegiate and Schwinn Traveller were essentially upright bars on ten-speed frames.

My 86 year old friend put ape-hanger handlebars from a 1970's Stingray on his road bike. It looked goofy, but he didn't care. He said it kept his arm pits cool. John is such a cool cat anyway, he is always experimenting with bikes. In fact, he was one of the first guys I knew to try the Landrider bikes with the auto shift, but he quickly dismissed it as junk.

Remember that if you switch road bike handlebars to uprights, your sit position will put more vertical weight on the seat. You will want a different seat - wider and maybe with some springs.

As for anti-flat goo, forget it. You end up carrying the extra load from the goo in the tires 100% of the time and it doesn't really prevent flats. Just patch the tubes when needed.