the final strip on a strip build can be challenging....and i have had similar long, narrow, pieces be part of that final strip challenge..

so the first thing i would say is you don't need to remove the cove or bead of the strips adjacent to the final strip if the strip can be physically inserted absent removing the cove or bead.   in general, removing the cove or bead makes making a hard-to-fit strip even harder.

my approach to last strips like this is to recognize that you will fiddle with this piece for a long time....and to work it slowly....and just be patient.  on something like this, i would go so far as saying i might allocate a whole work session  on one strip....and if i happen to go faster...well that's just icing on the cake.

more mechanically, i find that scribing a line on the wood for a rough fit, cutting close to the line with a saw and than a block plane plus a sanding block with 80 grit paper is kind of my main tools for this work.   there are going to be lots and lots of test fits and i find that i will make the little adjustments that will allow me to advance the piece an inch or so at a time as i work the piece in.  i also find that a little pencil mark to identify tight points  on the strip relative to its adjacent strips, help me focus my block plane and sanding work.

as you work this, you will find the last couple feet of this strip (the pointy end) will be fragile and wispy....so you need to be careful (hence the patience).  i also find working on the side of a table where i often temporarly attach a strip to my bench to create a little corner that i can block the strip against can help me hold the piece properly supported as i work it.

on a final note, do be careful when you get ready to glue the final strip.  you have to move fast in applying the glue and pushing it into position as a long piece like this can easily bind to the adjacent strips when being inserted with glue and then you can't get it in all the way if you work too slow.

part of building is the learning process...you can't really mess it up if you just are patient with these last pieces.

for inspiration, a picture of my petrel which had about 8 pieces that match your description of a 'final strip'.   8 pieces...8 evening working sessions :)

i just took it slow 

h