on our system we put a white strip evenly along the T track at eye level, thats your out trim. Spike tape hits that mark and you are at your out. On the in we go just above the lock with a different color of spike tape.
What DuckJordan said is what Ive seen across Canada. T track for out above lock in show colour or act colour for IN. We also do a spiral on the line as a warnìng for the In for fast fly's
We do mostly one-off's and short runs so use 1/2" colored gaff tape, on the inside and outside purchase lines at eye level.
Some ropes (1A Elec., borders, shell ceilings) have semi-permanent tape, where we use 2" white with a 1/2" colored on top of. The crew learns that such a marking does not get removed at strike.
One space I frequent uses the top of the rope handle for in and out.
Another space (and my preference) uses 2 fingers above the rope lock. Traveling shows that come in use one color for in (green), one color for out (red), and then a color to signify in between spikes. House spikes were all orange for this space as well. (for borders, legs, traveler, and cyc).
We have white synthetic rope. We use 2" gaff for most spikes. black for in, red for out, black with one piece of 1/2" yellow spike tape on top of it for low mid, and 2 pieces of spike tap on top of black for high mid. My electrics are usually 2" green gaff, and housesoft goods are red. And depending on the show this is all subject to change at an instant especially for a small show when there aren't any or only a couple of moves. At that point it just depends on what color tape I happen to grab first.
We have Multiline II for our hand lines. We use vinyl, or electrical tape. Low is red on front rope at the rope lock. High is blue on back rope in line with the last t track brace. Secondary hi is orange on front rope. Secondary low is green on back rope.
All lines are spiked using the same format. The exception is for a one off when I set low trims for the electrics. We leave the rep plot spikes on the ropes and use black for the day.