...... a) I asked and was told they were post mount and b) the calipers are using an 70mm spacing that looks like post mount but uses M5 bolts like flat mount. ......

......

So, now I’m wondering what calipers might be compatible with the LTWOO levers. ......

What I want to say is that Ltwoo does not adhere to any known standards, whether it's flat mount or post mount. Ltwoo has designed its own specification and provides a bracket with the kit to install it on most flat mount frames. Therefore, you will find that the included screws are M5 size, not M6. Additionally, this Ltwoo-specific specification was not initially designed to accommodate post mount frames, meaning it cannot be installed on any post mount frame.

As for the second question, it is actually easily solvable. Any Shimano hydraulic disc brake caliper compatible with mineral oil systems can be used with Ltwoo's control lever, including but not limited to models like MT200, M6100, R7170, GRX400, and so on.

You just need to ensure that the syringe, olive head, and hose are compatible. I recommend using BH90 components across the board because BH90 hoses can be directly installed on all BH59 compatible components. As long as you ensure proper hose installation, you don't have to worry about any compatibility issues.

I have paired my GR9 control lever with the UR300 flat mount caliper using BH90 hose, syringe, and olive head, and the braking performance and feel are excellent. I have been using it smoothly for nearly 5,000km without any issues of brake fluid leakage or loss of braking power. So, feel free to boldly pair them together.

Yes they do include a generous collection of hardware. Unfortunately a) I asked and was told they were post mount and b) the calipers are using an 70mm spacing that looks like post mount but uses M5 bolts like flat mount. Something I read tonight suggested that this is one flat mount standard (the ones on my road bike are much narrower at 30something mm) The included adapters are also 70mm rather than the post mount standard 74mm (seriously, who in the industry decided to invent a new flat standard 4mm different and using one size different bolts? ) I thought about drilling it out but there isn’t enough material in the right places. I also do not find anyone doing flat to post adapters for the 70mm flat variant.

And while you’re right about drop bar bikes being more likely to use flat mount, this is a gravel group set where post mount is not rare.

So, now I’m wondering what calipers might be compatible with the LTWOO levers. I know that early on they were bundling with other makers calipers, so I’m guessing the piston ratios are probably common. Maybe Shimano compatible since they went with mineral oil. If so, that would be great since apparently pretty much all Shimano calipers are compatible including across road and mountain groups.

Not sure about Ltwoo's electronic groupsets but I am running a GRX400 front caliper with my Ltwoo GRT groupset since the mounting brackets for their caliper were not compatible with my fork.

my er9 included all imaginable bolt lengths and adaptors for 140 to 160mm discs, something that costs extra and requires significant brain damage on Shimano. I think a very small fraction of the market cares about post mount (at least on the road setups), i wouldn't even want to pay for the shipping cost of bolts of another thread size. Shipping from China is a large portion of the cost of everything we ride in the West.

Yes they do include a generous collection of hardware. Unfortunately a) I asked and was told they were post mount and b) the calipers are using an 70mm spacing that looks like post mount but uses M5 bolts like flat mount. Something I read tonight suggested that this is one flat mount standard (the ones on my road bike are much narrower at 30something mm) The included adapters are also 70mm rather than the post mount standard 74mm (seriously, who in the industry decided to invent a new flat standard 4mm different and using one size different bolts? ) I thought about drilling it out but there isn’t enough material in the right places. I also do not find anyone doing flat to post adapters for the 70mm flat variant.

And while you’re right about drop bar bikes being more likely to use flat mount, this is a gravel group set where post mount is not rare.

So, now I’m wondering what calipers might be compatible with the LTWOO levers. I know that early on they were bundling with other makers calipers, so I’m guessing the piston ratios are probably common. Maybe Shimano compatible since they went with mineral oil. If so, that would be great since apparently pretty much all Shimano calipers are compatible including across road and mountain groups.

Not familiar with the name Delihea.

I note the shop listed on AliX on Oct23 only. Their business licence says ... ELECTRONIC commerce, established Mar21. So...
There are a few YT videos of people reviewing Delihea bikes, from much before 2023. From people buying on AliX.
Can't find a website for Delihea.

the ck-two that takes 32C looks VERY interesting. But that frame ticks all the boxes for 2024, i'd say.

I dont think i've seen this frame before. The other one with 28C looks much less future proof and relevant in 2024.