Levelling Parry
I
would recommend levelling PLD for increases to shield, parry, and healing! While it seems like this would take a long time, it is indirectly helping both your THF and WHM via the skillups you receive from regular levelling (and it's giving you another 75 job that a Galka just really shines at). Equipment and skill sharing between your THF and PLD would make this an awesome choice.
My parry is currently only like
228, most of it was done during the levelling of another job like NIN after THF was levelled. PLD will give you a perfect opportunity to remain as the primary target for VT and IT enemies all the way up to 75. Starting from 225, you can probably devise a way to cap it from there.
SAM, NIN, COR, and THF will have the same Parry cap. Working with any of those will allow a carryover after you've reached your 225 level.
I used to afk with a bunch of regen gear on in Citadel for a while in order to gain shield skillups. Garden Bangles, Presidential Hairpin, Snakeeye, /WHM, and the Orochi Nodowa would allow me to recover health lost while getting hit (up to +5/tic if everything was active). I'm finding that I can add ~ten skill levels at a pop if I devote a little time to it using what Mithrankittycat used to level on, the Yagudo MNKs in Oztroja's upper levels.
I've asked Kittyn how he was able to cap parry and he recommended upper level capping on Yvora. He was able to achieve 269 Parry on his NIN a while back and said those are the enemies that had allowed him to do it. I know I read a livejournal entry a short while ago about using the Pucks in DoR to increase; I think that's what Kalia was referring to (and it showed good results). I think it used aggro tanking in order to ensure that the hate never wavered. While I haven't spent any time lately towards capping Parry out, I'm probably going to use it as my justification for finally taking up SAM later on (I need to have a reason, right?)
There was an old way to cap out your healing, but I'm pretty sure it doesn't work anymore. I tried it recently and I was either extremely unlucky or it had been altered.
I'd go with what Fodder mentioned during Besieged, I've heard that this is an extremely quick way to level healing.