the LFL shown in the FMS PERF page, i use a Collins FMS6000 on the 605, is it the ALD factorized by 1.67?
Be very careful of using FMS data as the sole means to determine Landing Performance. Generally speaking, FMS databases like the FMS6000 do NOT respect "declared distances" and it is possible to inadvertently exceed max landing weight for a specific runway.
This FAA video addresses Declared Distances, aeronautical charts and FMS databases.
what kind of vertical clearance do you obtain when manually entering an obstacle in the TAKEOFF REF PERF pages - 35ft?
The best practice for calculation of max takeoff weight as well as development of One Eng Inop contingency routes is to engage the services of a professional performance engineering company like Jeppesen OpsData or Aircraft Performance Group. The FMS in the CL605 is not suited to that purpose.
This FAA video should help clear up the abundant misunderstandings on the subject.
Also see
AC 120-91 and links presented on
this NBAA page.