I have tried several different approaches to turn signals but found them very marginal. Using the parking light bulbs encased in a headlight shell such as found in pre-'40 cars are practical during the day but with the lights on at night they become virtually invisible. If you use fog lights you really need to operate the lights through relays. The small gauge wires often used in aftermarket turn signal units becomes a restriction to current flow to the fogs making them dim and difficult to distinguish even during the day.
What I have done is to use motorcycle turn signal units on my '35 and '36. In my opinion, the egg-shape shell looks period correct and bulb changing is a snap. Obviously, others have their opinions.
Tom