few keg pot still build questions/solder and flex in canada

[dendog33]

Keg colum to doubler to worm

1 solder and flex to use in canada.

2 should the pipe off the colum be 90 degrees then down or on a slightly more upward angle then down to the thumper.

3 i see kits that come with o-rings do the kegs need orings,ptfe gasket or both.

Last but not least 4 copper ferrule or stainless steel. I am leaning toward stainless and buying it already attached to copper tube.

before Iget ripped. I have been using an airstill and mak8ng tpw for a few year and have been reading about what to do for a while just wwondering if iI I can get some info from some of the more experienced members.
Any insights appreciated