Apologies I've been scrolling through the forum that long my eyes are going square.

What size profile rails should i use on a 3.5m Y axis for a 2.2m long X axis gantry weighing approx 150kg max total with ATC spindle.

I was originally planning 30mm rails but the more i look at them the more i think they are probably OTT.

Should i drop down to 25 or can i get away with 20s?

The router will only be cutting signage materials such as ACM, foam, 2-3mm ali, bit of MDF etc.

Kent