Frontier wood burner insert install

[Redeemed1]

Hello all and thank you in advance to any and all help, hints and advice.
I purchased a frontier 2 glass door wood burning insert made in the 80s that I am installing in the fireplace at my cabin. I may at most spend 7-10 days a month during the winter months there. Primary heat source is propane but looking to toast that drafty cabin up. The insert has a 14x4 rectangle flu vent ( please excuse my lack of proper terminology) on the top rear of unit.
So I know I have to get an adapter boot ,collar, liner ,cap. Several questions.
1)Its an older stove is it worth installing efficiency wise?
2)I have to make a cap on the very Flat top of my chimney. What gauge, type of steel do I use.
3) what type of sealer do you recomend
4)is there a one stop shop web site to buy all products
5)is there a cheaper solution other than the $120 plus adapter boot?
Again any advice would be appreciated

 

[begreen]

This old stove was designed for a slammer installation which is no longer allowed.

1) no, modern stoves are much more efficient
2) the stove should be connected to a stainless steel liner in the chimney. A top plate sealed to the chimney top will hold the liner and there are caps designed to top this off
3) ?? for sealing what?
4) Yes, there are some, depending on what needs to be done
5) The adapter boot connects to the stainless liner so this will not just be a $120 job