As I already mentioned, there's no need to implement exact inductance values or L1 and L2. For L1, you can derive from the resistance values, that it won't make much sense below 10 or 20 uH. But only high permeability ferrites would achieve similar inductances with 4 turns. so I'm not sure, if L1 serves a purpose at all. L2 can probably work with less inductance. In any case, I think a small fixed inductor will be the easier and less expensive variant.
You are right, that 1 uH can be achieved with an about 8 turns planar coil. Personally, I won't like the stray field and prefer a fixed (ferrite core) inductor as well.