Awesome! Thanks for great feedback! Now I feel much better to know that I actually was on the right track ;-) I'll be going to Lowe's today.
I had experience of resealing one tank but it was with little metal tube thing for one of 10 gallon and it was just horrible trying ot use that tube... hard to use so I want to use tube thing where you can just use it like chaulking ;-) And I might custom build a bigger tank too.
Again, thanks for great feedback.