"Fly runway heading" hdg bug centered on rwy numbers, hdg mode selected on departure - AP engaged
"Fly straight ahead" hdg bug centered on rwy numbers, through when gear and flap up divide x wind by two and turn hdg bug into wind by that amount, probably have the back course displayed for orientation - AP engaged
Worked for years, you will find some people
want to create a virtual waypoint 10 miles out on the extended centreline and fly it, head down trying to program this imminently before departure is just folly... ever seen the AA video children of the magenta.....
Invariably its only straight ahead for a minute or two until seperation is achieved