Bubbles and such
I make toys for my grandkids. Needless to say, they will be abused. Toy cars run into walls and each other. Anyway, i prefer Minwax brush on poly for it's hardness and also for the slight amber color it imparts to the toys. They make a water based version, polycrylic, that won't add color to the finished product. What i've found works best is a foam brush applying as thin a coat as possible. Don't shake the can or wipe the brush on the side of the rim as that will add air bubbles. Apply the finish but brush as little as possible. When the area is covered make one last pass, along the direction of the grain, tipping off the poly. That means running the brush over the poly as lightly as possible to help break up the larger bubbles. The smaller bubbles should disappear as it dries. After it dries, anywhere from 12 - 24 hours, I lightly sand with 320 grit, vacuum the dust and wipe with a clean lint free rag. Then apply the 2nd coat. i alway apply a minimum of 3 coats and as many as 5 for the front and back of the cars.
Unfortunately, in my tiny shop, I don't have a dedicated area to finish my projects. I try to let the dust settle as much as possible before i finish. What also helps with airborne dust is a simple trick using a cardboard box and 4 dowels. I cut the flaps off the box and tape the dowels into each of the 4 corners so, when the box is turned upside down it looks like it's on stilts. the box is big enough to cover the project on all 4 sides but the dowels leave about a 2 inch space around the bottom so there's some air flow. I keep it that way for an hour or two, until a skin forms so no dust will stick, and then remove the box to let the finish cure. I hope this helps.