That is awesome Joria! Thank you for doing that testing.
Just make sure to cancel the action as soon as they stick their spoon in the bowl. The first time I tried this I waited too long and the cook went ahead and put it in a pan and baked it.
I also always choose 'Store' as soon as the finished dish hits the counter or table. If you don't have the Super Fridge yet, or are not planning on getting it, this way you always have Perfect meals. I'm assuming you didn't get/use the replicator until your cook is always cooking Perfect quality meals. That way, I replicate the meal I want to serve, the Sims eat, and then I put the leftovers in my (Super) Fridge.
As for LTRs, I usually get Observant first, then I decide what to get them next based on their LTW and any skill related to that, like Super Green Thumb for cooks who garden or for Sims that are living with a Sim who cooks. I do the same thing if one of the Sims has The Perfect Aquarium LTW. Observant can let you know if someone is a Natural Cook which is handy in learning those recipes, particularly when you're playing a no travel Challenge or you have problems/bugs when you travel. I choose Faster Learning instead if the LTR points are slow in coming, but I always get it. That usually gives things enough of a boost (after I use it for a bit) so I can get the higher point LTW aids. After that, it's Steel Bladder and Dirt Defiant. No Bills may come before those if the bills are getting to be outrageous. Never Dull is also great for Sims pursuing Charisma, and fairly inexpensive, to boot. Long Distance Friend is good for any Sim that's pursuing Charisma, but when I get it depends on how much time the Sim has to socialize. And Meditative Trance Sleep is definitely in the range of the first few LTRs I get. Lately I've been trying Attractive to boost high Charisma Sims (the ones who are Friends as soon as they meet someone) even more. I haven't given the Charismatic Trait to a Sim since I've been using the combo of Observant, Attractive, Never Dull, and Long Distance Friend, though it's probably slower going at the earlier levels of Charisma.
I've also been trying Multitasker. I've yet to try Hardly Hungry because you lose the mood boost you get from a home-cooked meal, but I may try it with Sims that seem to be elated almost all the time anyway. Collector varies in importance depending on the Sims' LTW or if they've completed it and have free time. Carefree is on the list, but I've not made it a high-priorty LTR to get.
Finally, The Teleportation Pad is something I usually only get when I've gotten everything but a few lower cost LTRs that might be useful. If you get the TelePad, it's important to have a Sim with 10 or close to it in Handiness. If they don't have the Handy Trait or they're not near the top of the skill, save before you try to fix it or call the Repair Sim! I'd only used it twice when it broke, though I don't know if that's typical since I've only gotten it in one game. I'm playing a game now where I'm using the Replicator (upgraded) for the first time and it's definitely a timesaver. But my cook is only a couple dishes away from meeting the 75 Perfect meals challenge now, which is supposed to lessen the amount of time it takes to cook, so I'll see if it's truly worth the Points (particularly if you have the Super Fridge) in time saved.
Edit: Forgot about Meditative Trance sleep, so I added it.
Edit 2: And I forgot Never Dull, so that got added.
