so about all I know on this is that if the implicit rate is known to the lessee, we should use it over their incremental borrowing rate.

Is there anything else I need to know?  And I only think I know that, I am not 100% sure on that :)

As per Becker review ,

 Discount/Interest Rate to be used by lessee : LESSER of

i.) Rate implicit in the lease (if known)

ii.) Rate available in the market to lessee (not prime)

The same rule would apply to lessor also.

rate for leases

a)incremental borrowing rate of the lessor

b)implicit rate(by lessee if known by lessor)

whichever is lower

not sure.