Hi wxkristin, You should have the concern. A lighter weight floating floor like 3/8" is quite much harder to perform the same asa thicker and heavier one. Here are the 3 main things to have a sound instaled floating wood floors: flat subfloors, quality underlayment, heavier floors with good wear layers. Good luck with your project.

For 3/4" x 5" , You will need to do a nail assist installation, which is a full troweled glue as your main fastener and cleats or staples, spaced 18-24" as secondary fasteners. This is standard installation practice for wide planks. The alternative is to do a glue assist, which is the opposite of a nail assist and much more tedious. Beads of glue is applied in a continuous "s" pattern on the back of "each" flooring board and nails/staples are at 6"-8". The nail assist is a better and faster install, but not the cheapest. With the correct type of adhesive, the adhesive acts as a vapor "retarder" , not trapping moisture on or above grade installation. More prep work is involved. If, the installer does not have familiarity with adhesive types. Have them use the glue assist method to stay on the safe side. Or find someone who is.

go with the larger. the smaller size is more suited to older homes. is this the look you want? here's the narrow one to me, this is better suited for a more traditional home. not a young persons condo. these are also the gunstock Oak in wider widths is there anyway you could change the choice from gunstock and go with something like this instead? http://www.pcwoodfloors.com/product/prefinished-engineered-oak-mohegan-916x-6/ http://www.pcwoodfloors.com/product/prefinished-engineered-oak-matcha-916-x-5-6-7-12-4mm/ or maybe this natural white oak engineered? I just think these finishes and colors would be more appealing in the coming years http://www.pcwoodfloors.com/product/prefinished-engineered-white-oak-12-x-5/ or maybe do random widths and get both of the narrow and the wider widths

When it comes to "trends" vs. "timelessness" you want to look at your personal timeline for selling. Are you planning to sell in the next 5-7 years? If so, go with the trend and ignore your own tastes. If you sell in a few years then you are not buying/constructing the home for yourself. You are creating it for the NEXT buyer. If you are in it for the long haul (7+ years) then you put in the floor that makes YOU happy and that makes YOU smile and that makes YOU feel better about your choices. If you want flooring that can be "extended" into other areas for a later remodel (like in 10 years time) then work with the 3" product. It will be around for a long, long, long time. Wide planks are trending HEAVILY right now. They come and go. And if you are in there for 10+ years, you will want to have the option of refinishing so that when it comes time to sell, you can update your floors for $5/sf instead of having to pay someone to rip out and replace the floors ($10+ per square foot for a job like that).