Watch - ECG Inconclusive >> Poor Recording

Just wondering if you've found the ideal conditions for taking an ECG with the Watch... I upgraded specifically for this functionality as I've developed heart issues over the last year. More than 50% of the time I'm getting Inconclusive results due to a "Poor Recording." Have you found the best placement of your arm? The "right" finger? Fingertip or pad? Light pressure or firm? I'm becoming increasingly frustrated and would love any feedback you have!