This will do the work:
Set layerMgr = swDraw.GetLayerManager() 'LayerManager object for the drawing doc object
Set swLayer = layerMgr.GetLayer(LayerName)
swLayer.Visible = True 'Turn it on ,Or False to turn off
You can copy a sketch with all of its dimensions. Select the sketch you want to copy, CTRL-C to copy, select the new plane and paste (CTRL-V). Don't open a new sketch before you paste, and you'll get all the dimension and relations.
You can also copy a feature by CTRL+drag the feature to its...
The use of CONFIGURATIONS is the best practice for handling large assemblies (not just in drawings).
You can have a simple configuration of components and simple configurations of the assemblies. It reduces size and resolves much faster. If you have an assembly of 500 components you probably...
Loft seems to be the right way to go here. However, If you know how the guide curves goes along the tube you can use sweep with guide curves to change the cross section while sweeping.