If I was starting from scratch, I would consider one of the aftermarket motorcycle electronically-timed self-cancelling devices that use 2 momentary contact switches. I'd mount either pushbutton or toggle on the dash. A side benefit is you get the emergency flasher function for free. I drove MGA's for many years and never felt like reaching for the dash was an inconvenience to activate the pneumatically timed turn signal switch. As a matter of fact, my Locost uses the RX-7 switch mounted on the dash in a similar location and operation. The RX uses a potentiometer mounted on the steering shaft housing to sense the wheel turning for self-cancelling.
One benefit to the RX or motorcycle system is if you are planning on using a removable steering wheel. Steering wheel mounted push buttons require wiring and a disconnect. OEM style steering shaft stalks remain in place and may be subject to damage while trying to get in and out. One disadvantage is not being able to reach the dash to activate the dash-mounted turn signals when using a 5-point harness, unless you have ape-long arms.
I re-designed with 3-point inertia harnesses.
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Chuck.
“Any suspension will work if you don’t let it.” - Colin Chapman
Visit my ongoing MGB Rustoration log:
over HEREOr my Wankel powered Locost log :
over HEREAnd don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766