Fuel cell vent/anti slosh?

Anyone have experience with an anti slosh vent? The fuel cell I’m using (http://www.ebay.com/itm/400936754194) has two -10 fittings in top. Currently one is capped and the other goes up then down to outside of the car via a bulk head fitting.

Under launch with a full tank it leaves a stream of gas on the ground. Will a standard flip-over type valve also help with the slosh? https://www.anplumbing.com/extras/fuel-cell-accessories.html?p=3

all the ones i have had have a ball style check valve in one of the top ports
yours doesnt?

No, it just has empty - 10 ports. I ended up getting this : https://www.amazon.com/dp/B007VR9Z4W/ref=cm_sw_r_cp_apap_Iy5Ku6jTn9uJs

Installing tomorrow along with this: https://www.amazon.com/dp/B01L0YQQ4I/ref=cm_sw_r_cp_apap_zORShwMnNdLeT

Should I use some permatex motoseal (or something else??) or are they usually installed dry? There is a gasket for between the neck and tank and nylon washers for under the nuts. I’m thinking a light coat won’t hurt.

Pictures tomorrow!