So, watching Vinesauce's playthrough, I finally found the location of the Granter of Boons, a.k.a. the Horned Statue, and confirmed he trades heart containers for stamina vessels. If I understand right, the cost comes down to a total of 20 Rupees for each switch.
So, it occurred to me two ways to speed things up.
First, when you're just a few hearts away from 13, trade stamina for enough hearts for the Master Sword. Then trade them back after getting the Master Sword.
Or, once you've got the Master Sword through getting 13 hearts the old-fashioned way, sacrifice a few hearts to get max stamina way earlier.
I'll probably try it on my tenth playthrough, which might be sooner than I think coz I'll be trying a few things I never did before.