Silver braze, 1% or 15% for refrigeration tubing

Years ago, I bought a pack of brazing rod with 15% silver content. Used that to join refrigeration tubing. Turns out that Mapp gas torches work well with the 15% silver braze.
My old boss introduced me to Sta-Brite silver bearing solder. Much lower flow temp, but doesn't seal voids as well as stick braze. If it's old copper, or of there is a bit of gap. I use the stick braze.
The Johnstone catalog says the 15% silver has about the same melting temps as the 1 to 2%. I don't know if I believe that. I used to braze with mapp gas and the 15% stuff. But, tonight I just couldn't get the map gas flame to heat the fitting hot enough.
Has anyone tried both, and is there a real difference? I'm tempted to go buy a pack of the 15% stuff, save me having to haul out my acetylene torch. It's easy enough to carry a 16 ounce tank of Mapp in my tool box. On the other hand, I braze about twice a year, and for that once or twice I can use acetylene. When I did get the acetylene torch out, it did a nice job.
Christopher A. Young
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