I don't own these particular frames, but I do have a Lightcarbon gravel and a VB-268. Contrary to what some might believe, the VB frame is of noticeably higher quality in every aspect. However, I wouldn't recommend building it with a mechanical groupset, especially if you're using an integrated cockpit. It's possible, but it can be a major hassle. You'll likely end up with less precise shifting and other issues like tight or unbalanced steering.
Thanks for your feedback.
The reason why I would go for mech. shifting is that I´m totally happy with that and I already have most of the components to build a new bike.
Did you experienced this difficulties yourself?
Even with an electronic group the brakes lines would be there and I´m not sure how big the difference would be adding the shifters cables which are not so stiff as compression-free mechanical brakes sleeves.