How much of the gal to give her?

Anchor the bottom of that plant, it it'll slowly pull itself through the substrate or worse, tear some roots. You can also bend it in 2-3 spots very close together at the bottom. this will take stress off the anchor / lower trunk / roots. Form a bend before you tie it down. You do not have to damage the stem (unlike you typically do for HST / supercropping). The more level the resulting bend-over is, the more evenly--distributed the growth will be. 2inch deep dry is probably more than long enough to wait for an irrigation. Your leaves are still perky, so it's not "too long" either, but you could probably do it a bit sooner. 1-inch deep is typically enough. You give enough to get the job done. No dry pockets... fully saturate. In soil, some minimal runoff ensures this and won't leach out too many of those amendments you paid for that came with the soil.