Hi there!
Regarding the KB arrival...as you mention routing the arcs I am assuming you will be following the RNAV1 transition?
In that case, and considering your lunchtime/ weekday plan, you should find there won't much use of the arcs at that time of day. We use them primarily during spikes of EGLC traffic, for accurate intermediate approach spacing. No guarantee, but you should route JACKO-BABKU-RAVSA at that time of day at the very most, subject to activity at Shoeburyness (EGD136-138).
I am still a TC trainee, and I do not have much experience with how routing a flight like yours would work. You may be able to request ad hoc routing via SND, staying west of the danger areas if active, and remaining on shore.