I also don't know how long it took IchoTolot to figure out his solution to Legend 07. He was pretty fast at solving the pack overall. I sometimes couldn't keep up, actually. 
Right, that's the bad thing about not solving anything in real time on camera, as you don't get to see what about the level the player struggled with and similarly if there wasn't any problems solving it. According to the timestamps of my replays, it only took me about half an hour to solve Legend 7. In contrast, it only took me about 10 minutes to solve Legend 4

These really quick solving times generally indicate I didn't have any problems solving them, although I personally consider myself having struggled with any level that takes me longer than 15 minutes to solve.
Lol I was the same way when I went through this pack. I was solving way too quickly, particularly when I kept coming back to post replays for both the first and second half of a rank all in the same day, that you couldn't even keep up. I still don't know if you ever gotten around to seeing all 320 replays, as well as have had a chance to read all the feedback, but well that's on you. No pressure and hurry of course, as always. You know me when it comes to being super detailed

You've misunderstood me again.
You made the claim that "You don't know that LPing is difficult until you've tried it yourself". I didn't question that it's diffcult; I questioned the claim that you can only know it's difficult once you've tried it yourself. I realised that from watching alone. So you don't have to make me try LPing a pack to know that it's more difficult than playing by yourself if it is already difficult enough for me to solve custom NeoLemmix levels anyway. 
Actually, I didn't misunderstand. It was in response to "you can only speak for yourself." I'm simply saying that LPers are pretty much in agreement with me that it's difficult and hence "I'm not alone there." Again, a lot of things are difficult to tell how they would be without actually doing or trying it for oneself, but yes, I understand where you're coming from in regards to determining LPing being difficult without necessarily needing to try it, which makes perfect sense if you yourself consider a lot of the packs too difficult for you and that you have had plenty of your own struggles with them and actually needed a hint or two on some for a nudge in the right direction.
That being said, I don't exactly know how well you would fare against the very first Lemmings levels I have ever made. They're current LDC levels, though, and I know how you are with not playing contest levels in general. From the feedback I've been given, everyone's been kind enough to tell me that they consider my R1 the hardest out of my 3 entries even though they come nowhere near the hardest levels ever released in a pack. This comes as a surprise to me, as I always had this thought that I'm no good when it comes to making a difficult level, let alone a contest worthy one, but hey, surprise! Apparently I'm capable of making hard levels myself. Keep in mind these are the very first levels I have ever made

Also, I still rather solve than make them

It's interesting really, as lately I've been asked by various designers if I want to test out levels for them, which I of course gladly accept the offer

By seeing other people struggle and raging at levels in my packs already, which, as we established, are still easier than most other custom packs by long-time forum members, I can only infer how much those same players would struggle if they had to solve those harder packs on camera. That's why even long-term Lemmings Let's-Players tend to go into post-commentary replay mode on the higher ranks of those packs, instead of continuing to solve them live on camera.
Luckily I haven't had to do post-commentary yet, although there have been a few levels which I needed to spend some time off camera before coming back to record and attempting to reproduce the solution by hand rather than load a replay. Even if I encounter a level that I've already played and solved before, in general I don't ever load replays in my LPs. I don't mind sitting through and trying to figure out a level all over again, just because it's kind of beneficial to do so, especially to exercise one's mental thinking. Also, if I generally can't get a level solved after at least two videos, then I spend time off camera with it.
Of course, this might have to change with some future packs I LP. Here, I'm thinking LPV and LPO2 might need post-commentary after some point, but I would only do this if it's clear that I'm just not enjoying myself solving these packs on camera and I wasn't liking the persona I was putting on on camera. I've done so many LPs at this point, and except for maybe a level or so where I kind of raged (I say "kind of" because it kind of borders on me nearly erupting out into fury but it's clear that I'm flustered and slowly getting annoyed based on my tone in the video), I seem to have a lot of patience compared to most when solving on camera.