I have done it just about every which way with my Foundry and it seems like a very slow recirc is required (even with a bag lining the basket or just using the bag as the sole filter) or I just skip recirc and batch sparge after stirring the main mash periodically during the mash, along with pulling up the basket two or three times in the mash process to get a thorough rinsing of the grains. If doing a recirc, the tubing constrictor needs to be tightened down significantly to get the right recirc rate...I also have a locline halo arrangement that I use with the bag in the basket to make sure it is returning to the top of the mash in an effective diffuse manner. I ditched the mash diffusion plate on top for most mashes as a result of the locline being so much better as a top return manifold.
The narrow diameter of the Foundry creates the need for added attention to this detail, though I have little to no complaints with my Foundry unit (I especially like the switchable 110/220V alternatives it provides). Cheers.