I use assembled circles of FT Tracks, and slide single tracks, right on top of the FT Track spline points.
I also use the Trainz ruler, and make radiating wagon wheel spokes from a central radius, and place spline points there.
I also use the Trainz ruler: (as I am trying to make a screenshot right now ... pending)
I tried all the curve guides, and they are way too huge in radius.
Those "track alignment tool" by arjen-0, are great for making 5m track spacing yards, but I like to set my track spacing at 4m, so those are useless for me.
I use the Trainz "Get Curve Radius" tool button in the track/advanced tab, extensively, and I like to keep my track radius @ 500m to 800m
I also move my last two spline points on a curve, outward @ 25m, as this makes for a smooth track easement transition, from straight to curve.