Please forgive/correct me if I am wrong but I thought that the certification basis for all types takes no account of the contribution of reverse thrust in the calculation of landing roll distance required
Dry - yes. Wet - no - IMHO
i.e. in the Wet, Reversers are assumed to some extent, and why "1 Rev U/S" MEL requires no Perf corrections in the Dry, but does in the Wet...
But you miss my main point
To await selecting Reverse until you see the spoilers out, and presumably "touch and go" if you don't see them (?), is a complete new SOP / Performance issue. All training I have done to date is basically once you touchdown do all you can do to stop ASAP
That means selecting all stop aids ASAP - not a flow diagram of A, then B, and if you don't get A then try C