A few tiling questions

[cdbe]

I'm starting with the floor, it's (so far), first floor timber, t&g boards, SBR, flexible adhesive, 6mm cement boards screwed into the adhesive.

The tiles are 600mm porcelain. The floor is out by no more than 4mm over the length of a 1200mm level.

Can anyone advise -

size of trowel (and whether round or square),

type of adhesive (will definitely be standard set at the speed I work),

a suitable leveling system (I have the floor - about 10 tiles and the walls - about 50 - it's a one off job so something economical

grout line thickness (I'll be using matching grout),

on the general layout, I have plenty of tiles so I'm not having little cuts, but wonder how far into the door opening I should go? I'm thinking they should finish at the outside of the closed door with my transition (from the lower laminate outside) just covering any tile visible from outside?

And just a general question about the leveling systems (as always people on YouTube just made everything look easy) but how are they to use in practice? Don't they just lift the tiles off the bed, or is the actual amount they move so small it doesn't happen (assuming the floor is within an acceptable tolerance)? Should my adhesive be runnier, or the bed thicker or am I just overthinking this?

Thanks

 

[Odds]

Only 4mm out over a distance above a meter?
You lucky beekeeper!
A large trowel would be good, i prefer square to get in the corners, and a sticky consistency in the adhesive, easy to spread but not so simple to pour. Is it a wetroom?
If you have time maybe a dampseal course would help keep things dry underneath the tiles, which i usually give a 3-6mm grout line, depending on pattern or plain.

 

[cdbe]

So 4mm is good! It's not a wet room so I'm not going to try and tank it.

With the trowel, I meant square or round notches - I don't understand the difference and just want whatever's easiest for a novice to use.