ShoeGoo, Amazing Goop and McNett Seam Grip are the same plastic with different viscosity, listed from thicker to thinner.
In any case, thinner applications give better results - less likely to peel and much, much lighter. Popcicle sticks or tongue depressors are good for spreading the sealants and for scraping off any excess. You can also use plastic squeegees, but these adhesives will stick and ruin them.
If you use wooden sticks to spread, lean the sealant, viscosity is less critical. Goop and ShoeGoo are much cheaper than McNett's Seam Grip.