sort coins by amount first

src/operations/pay.ts

@@ -185,10 +185,12 @@ export function selectPayCoins(
   }
   const coinPubs: string[] = [];
   const coinContributions: AmountJson[] = [];
-  // Sort by ascending deposit fee and denomPub if deposit fee is the same
+  // Sort by available amount (descending),  deposit fee (ascending) and
+  // denomPub (ascending) if deposit fee is the same
   // (to guarantee deterministic results)
   acis.sort(
     (o1, o2) =>
+      -Amounts.cmp(o1.availableAmount, o2.availableAmount) ||
       Amounts.cmp(o1.feeDeposit, o2.feeDeposit) ||
       strcmp(o1.denomPub, o2.denomPub),
   );