Viola Double-Stop Perfect Fifths
The standard method of playing a double-stop perfect fifth on a violin is to place a single finger between two strings. What, please, is the standard method of playing a double-stop perfect fifth on a viola?
Placing a single finger between two strings and hoping for the best.
It’s called faith ;-o That and a quick ear and hand
Perfect fifths on viola are an oxymoron. Could not resist the temptation!
Even on open strings with planetary, when the violist is also a good violinist, Rocky?
I've heard rumours that perfect 5ths are a tricky one for violists. However, being a violist myself, I can play perfect 5ths problem-free, and the method is the same as violin.
If you have thin fingers like mine, you could try 2nd + 3rd where you would normally use just the 3rd finger or even 3rd + 4th fingers.
Stay in low positions and use the 2nd or 3rd finger. The strings get farther apart moving towards the bridge. If your finger tips are not wide enough maybe play violin instead? Thin fingers are a real advantage to tuning those pesky 1/2 steps high on the E string. ( Perlman being the notable exception.)
Outside player plays the top, inside player plays the bottom. Easy peasy.
Called multitrack recording aka overdub. Alternative: pickup and vocoder or sampling delay.