Hi Voodoo, following is my opinion only (you know what they say about opinions !).
Over the past 26 years I have had a total of 3 different .458 Lotts.
# 1;
The first was a Win mod 70 with a 20" tube that I used extensively on buffalo and feral Oxen for a number of years and also took that rifle to Zimbabwe where I used it successfully on Cape buff and carried it for untold miles chasing (and being chased by !) Elephant and absolutely LOVED that set-up.
Unfortunately, after the use and abuse of years in the Tropics and untold hundreds (maybe thousands) of rounds, this particular gun developed traits of wear that could no longer be ignored in a rifle being used for back-up and with the repair costs exceeding the total value of the gun itself, I made the fateful decision to trade "up" in to a new gun.... as the Cz 550's had just then come on to the market and I was swayed.
Big regret.
This original Lott was my favourite by a country mile.
Exceptional balance, fast handling in tight spots, able to swing and point like a shot-gun and very little appreciable loss on velocity. Positives far outweighing any negatives.
# 2;
The second was a Cz 550 which from memory came with a full 25" tube.
The year I bought it I did my own mods (no AHR on this side of the pond

) by stripping the stock and re-shaping it, taking over a pound in weight off the gun and thinning it down dramatically, making it far more comfortable to handle and shoot.
I also had my gunsmith fix the feeding issues, exchange the trigger, front and rear sights and install a proper kick pad on it and, again fatefully decided AGAINTS lopping the barrel down, leaving it the original length.
When this rifle was finished, the stock was MUCH more comfortable to hold and handle, the trigger was a pleasure to operate, the sights were actually visible... BUT the barrel length bugged the crapper out of me.
I carried and used the gun for one season then sold it on to a mate of mine who is currently still using this very same rifle as his main back-up gun on his guided buffalo hunts and even he is constantly fighting the decision to lop the barrel or not.
# 3;
My current Lott is a custom built Win mod 70 control feed with a 22" barrel, total weight at 8.5lbs and, although this rifle is extremely comfortable to carry and shoot, I really regret going with a 22" and not a 20".
I fully intend keeping this current Lott as it is extremely well put together with quality components and have not ruled out lopping it at some stage down the track. This would mean sacrificing the front ramp which of-course could easily be replaced.
To my mind, the length of barrel should be directly proportional to the profile of it (the barrel), as this directly effects the final balance of the rifle, and that will dictate how that rifle "feels" during use,
dependant on the use you have intended for it.
If you get the profile versus length correct there is no practical, nor logical, reason to exceed 22" on any Lott and if you are particularly fond of fast handling and naturally pointing rifles then do some research on barrel profiles of the particular barrel on your gun and consider 20".
I can highly recommend it.
Congrats on your decision on having your Lott given the treatment by AHR, I've had several buddies do the same and to a man they have ALL been extremely satisfied with the results.
A far cry from the original factory product from Cz.
Gotta LOVE the Lott; it is, in my mind, the very best of the available factory big bores in a bolt gun
Best of luck,
Paul.