I'm getting a little tripped up regarding proper insulation technique for new construction interior basement walls. For reference my basement doesn't have exposure and sills are spray foam.

From building science: https://buildingscience.com/documents/information-sheets/basement-insulation

The best insulations to use are foam based and should allow the foundation wall assembly to dry inwards. The foam insulation layer should generally be vapor semi impermeable (greater than 0.1 perm), vapor semi permeable (greater than 1.0 perm) or vapor permeable (greater than 10 perm) (Lstiburek, 2004). The greater the permeance the greater the inward drying and therefore the lower the risk of excessive moisture accumulation.

From a contractor that referenced a different building science link

https://www.diychatroom.com/f19/basement-wall-insulate-ventilate-41111/

https://buildingscience.com/documents/digests/bsd-012-moisture-control-for-new-residential-buildings?full_view=1

In new construction the interior insulation and finishing approach must take into account the moisture migrating up through the footing. This is best accomplished by installing vapor semi-permeable rigid foam insulation on the interior of the assembly to protect the interior finishes and to release the capillary water to the interior in a controlled manner – at a rate that does not damage interior finishes or lead to mold.
The best foams to use have a perm rating of greater than 1 perm for the thickness used. This means limiting extruded polystyrene insulation to less than 1-inch thickness for walls (more than 1 inch thick and they do not breathe sufficiently) and making sure that the rigid insulation is not faced with polypropylene skins or foil facings. Additionally, since foams need to be protected from fire, and this is often done with gypsum board only latex paint should be used on interior gypsum finishes (since it breathes).
Avoidance of the installation of vapor barriers such as polyethylene vapor barriers,foil faced batt insulation and reflective radiant barrier foil insulation on the interior of air-conditioned assemblies – a practice that has been linked with moldy buildings.

Figure 21: Concrete Basement With Interior Insulation

Applicability – all hygro-thermal regions
The key to this assembly is the use of non-water sensitive rigid insulation on the interior that still permits drying to the interior. The recommended permeance of the interior rigid insulation layer is approximately 1 perm. This typically limits the thermal resistance of the interior rigid insulation layer and an insulated frame wall assembly can be located to the interior of the interior rigid insulation. No interior vapor retarder is located within the frame wall permitting inward drying. All interior concrete surfaces are wrapped with the rigid insulation layer – particularly at the top of the wall and at foundation “step downs.” Exterior rigid insulation is located at the rim joist floor framing to control summer condensation. When insulating sheathing is not used, rigid insulation should we installed to the interior of the rim joist or an air impermeable insulation be applied at the rim joist assembly. Note the capillary break at the top of the footing.

************************************************************************************************************

My two questions:

1) Is it best practice to eliminate an air gap between interior wall and interior basement wall, then use XPS (unfaced extruded polystyrene)?

2) If that is the case should the XPS be minimum 1" or maximum 1"?

As a side note I've talked to multiple local contractors and they recommend the air gap to allow air circulation.