LOP is probably the least important dimension as far as shoot-ability/ comfort is concerned.
13 3/4 -- 14 1/4 should make very little difference on a weapon designed for iron sights.
I am 6'3" and if I have my druthers I to like 14 1/4, but in reality, 3/4" less doesn't matter that much in the real world.
I would suggest you measure the drop at heel and comb of the two contemporary rifles you have and seem to be very fond of.
These measurements are way more important than LOP.
The Dickert/Lancaster should feel significantly different than that Virginia that Matt built you.
I would think that since most of your ML experience is centered around cookie cutter TCs, possibly you are missing out on the contemporary BP experience.
Part of gathering up guns from different schools is, they look and feel different and enjoying that difference.
If you were collecting original pieces, would you only purchase rifles with your LOP ?
I would think that a man with your discerning eye, knew full well that this weapon would not meet your standards, yet you decided to take advantage of Tracks return policy - Hmmm
Seems to me that moving from your particular field of expertise (TC) to Contemporary flintlocks is a great thing.
This move will require you to add to your knowledge base, another good thing.
You seem to want to gather this knowledge via the Internet (a bad idea) and ordering mail order brides sight unseen.
If memory serves me right, all 3 of these brides had issues.
Going to school is always cheap, regardless of how much cash you put out.
Bite the bullet,, spend the money and go up to Dixon's.
Pick up and handle/compare a hundred rifles.
Talk to/interview a couple dozen builders, take hundreds of pictures - There is absolutely no substitute for "Touchy Feelie" !
I believe that you could learn more about flintlocks, standing next to Eric K for three days than surfing the INTERNET looking at pictures for the next year.
Not wanting to rub you the wrong way but, standing next to Mike Brooks for a few days and just listen -no talking, would be a good second choice.
If you REALLY want to learn and gather up Good Quality Contemporary rifles you need to hold the rifle in your hand and look the builder eye to eye and ask and learn.
Keystrokes don't build good rifles, good tools, connected to good hands, guided by an experienced brain - builds good rifles.
Spend the money, go to Dixon U, There is nothing like it on the entire planet - Whats that worth ?