I have done some progress on my large hbot printer over last two weeks. I hope to get this project finished in a few weeks time. There is still plenty of things which have to be re-design and adjustments to be done.. here is a few photos and movies I made during XY gantry tests.
here are y axis belt idlers with added slot for core XY configuration (for fishing braid only..)
some tests using a pen
this one looks quite good
Pen is no the best tool for repeatability test, I planing to run test with one of my hotends as soon as I will put Z axis on it.