BD1791
Do you ask with respect to comfort or security?
And speaking of detached, do you mean with any sort of tools? I mean it's trivial and I hope you won't mind if I mention it, yet with the right tools, plus sufficient time and/or force, you can dismantle any belt. In this case, I'd say, if someone is reckless enough and unchallenged, a bolt cutter will probably be enough to "detach" the cable … 
Owl Do you ask with respect to comfort or security?
Yes.
Owl And speaking of detached, do you mean with any sort of tools? I mean it's trivial and I hope you won't mind if I mention it, yet with the right tools, plus sufficient time and/or force, you can dismantle any belt. In this case, I'd say, if someone is reckless enough and unchallenged, a bolt cutter
... No. I just want to make sure I can't just take it off. No bolt cutters involved
BD1791 tollyboy [...] but it appears he is no longer making belts.
A few months ago, he was still here. 
(Cp. https://unwedchastity.org/d/611-tollyboy-odd-jobs ) IIRC, he was about to relocate his business to Europe / Austria (?), but I don't know the current status. Hopefully he is well; ( @Taz ) hope we get an update, when the time is right.
BD1791 Neosteel offers an upgraded lock that's supposed to be very difficult to pick. I'll probably opt for that one.
Alternatively invest into more padlocks to change from time to time, plus a bunch of unique plastic seals that your keyholder signs and applies when maximum protection against lock-picking is needed. Might depend on circumstances, particularly your time, opportunities and skills for lock-picking, though.
Updated (2022-06-12 18:49 UTC): I should add, we have some experts on lock-picking at UWC, too. I'm almost sure they will be able to give a much more qualified evaluation on the intricacies of current Neosteel locks.
BD1791 oh... That's really good to know [...] complicated things a little.
Well, you came to a forum that aims to provide real help and quality information. If that means confronting people with realities that have some complexity … well, I guess you have to deal with that. :-)
I am sure you'll manage and won't regret that you asked here, first. Even if you eventually came out with exactly the same configuration you planned before, you can be sure that your choice is on a more reliable basis, then. Now after you approached the hawks of chastity. (Well some of them ;-))
BD1791 I originally wanted a tollyboy because his lock is supposed to be impossible to pick
I can confirm it, although @BikelockFugitive says different
BD1791 Neosteel offers an upgraded lock that's supposed to be very difficult to pick
I remember it was mentioned in The lock topic, and @HHelen even wanted to order one for her daughter
Yes, I wear 24/7.
For me is comfortable, even I feel I feel a little pressure on my buttocks just around the anus, but it's not uncomfortable, at least for me.
I don't even realize it anymore.
BD1791 How long did it take you to get use to it?
I spent several years using it only at night, but my cousin and my aunt started a few months ago and are used to it.
BD1791 I could get the cable and the opening and just see which one works for me. It's so hard to know without trying them.
We'll if you can afford it ... :-) Being able to compare the real things and decide for yourself seems great to me. (Though I can't offer personal experience with that modular Neosteel design mentioned, yet.)
(Semi-) Off-Topic:
While we're at it, order foldable D-Rings / connection adapters for accessories - ideally for at least 3 points (L/R side of the belt + crotch) - as well! Even if you are convinced they are extra, now.
Ines the Chastity Hawk and her relatives can surely tell you why it's always a good idea.
Or you may read one post I made somewhere else ( https://unwedchastity.org/d/657-thighbands-with-padlock/155 ). If you don't want to fight through my notoriously long, pseudo-intellectual babble - although parts of me suggest you do, ofc 
- I can give the extreme conclusion: Ordering d-rings / connection points for accessories is a chastity-wise preparation just in case, and an economically sound decision.
Small addition on modular designs in general:
Modular designs could involve certain alterations, like extra joints and screws or bolts to link the parts, which could annoy, e.g. pinch at worst, or require extra cleaning.
Please note: This is just a theoretical, general consideration, not one from knowledge of the current Neosteel Solution. I don't want to spoil nor advertise. Owing to the shop maintenance downtime, I can't double-check as well, atm. If you think that concern holds for your desired design, I suggest talking about it with Neosteel as well.
That being said, again: If you can compare different configurations first-hand, that's great.
