Prices on really good weapons that are not currently or recently obtainable in a prize shop or quest log pool are already through the roof - they have been since a plot was announced. Many of the retired HT items did come down in price when the capsule was only 10 mil, but the better ones are already starting to go back up again. That being said, you probably have (or have access to in a prize shop) plenty of ones that will be more than adequate except against the most difficult challengers.
You might be able to beat GHMC, especially since you've got the max strength boost. Lens Flare + 2 hard hitters for round 1, then Warlock's Rage + 1 hard hitter & 1 freezer for round 2, then 2 hard hitters + Icicle for round 3 would get you a good start at the very least - you shouldn't be touched for those three rounds, so it's a question of taking him out round 4 if you hadn't already done so. Just remember that T-Tear does NOT prevent abilities, only weapons.
I refuse to zap-train my battle pet. I spent WAY too much time evening out her stats after having zap-trained her to begin with (and thus suffered in the Curse of Maraqua plot as her HP was way out of proportion from her other stats). I also don't want to deal with losing too much defence and certainly not the constant level training that I'd have to do in the end.
That being said, if you're not set on a Tonu, you might consider morphing her into a Pteri, since they can be cured of any disease by feeding them something with "worm" in it (which will also make them bloated).
As an added bonus, you could then paint her candy had have her fight in the BD as a giant Peep Kitchen quests have been good for me, training-wise. I don't restock often and mostly just rely on user shops to get items (which, true, takes time to price out, buy, etc), and I don't spend more than 30k on a quest. Most days I spend less than 100k for all 10 quests. I've also sold a bunch of the items I've gotten as rewards (totaling at least 1/4 of the cost of what I've spent). Not accounting for the items I've sold, I've spent about 19k per stat. If you count only levels and hit points, it's about 40k per stat. The fact that it gives out slightly less than 2:1 HP:Levels means I'm usually getting enough levels off the quests to focus solely on spending my codestones training HP.