If I may remind the readers of this post % in-lair something left unsaid was the means to determine encounter numbers.
Let's reqoute the basics (from p25, of the First Fantasy Campaign, 1980 reprint)
"the number of creatures encountered will then be any number up to the total number present in the hex. Again to avoid confusion, you may wish to take the maximum number of creatures that are listed on the Monster Matrix as representative of the population in the hex for each encounter"
So after determining the monster type encountered in the usual fashion, (step 1) you use the "Number Appearing" column to determine the population count of a given lair in a given hexagon 5 miles across.
"For each time that the creatures are found in their lairs, there will be a chance that a portion of them are out in the countryside. To determine this number, assume that 40% of the population is always in the camp and that up to 60% (10 - 60%) are always outside of the camp."
(step 2) Determine how many are "in Lair" and how many are "Wandering". Roll 1d6 *10 = percent of population wandering.
Now determine where the groups are, and how many are in each:
"Roll a die again and see how many miles (1 - 6 miles) they are away from the camp. On a roll of six, the creatures outside of Camp are in two equal sized groups, and you would roll again to determine how many miles away they are. Note: Whenever sixes appear again, divide that proportion of the creatures in half again and roll for their positions. In this way, an original group of creatures starting at, say, 50 strong could first divide into groups of 25, then 12, then 6, etc.
Example: 50 Creatures, a six is rolled:
A) The first group of 25 is located 6 miles to the northwest.
B) The second group is divided into 12 and 13 Creatures; the first being located 3 miles east of camp and the second rolling a ''6''.
C) This second section is located 4 miles south of the camp."
So,(step 3) locate the "out of lair" group using the direction table and a d6. If a 6 is rolled, split the group in two and locate as before".
So, as you can see in the example, whether you stumble on the group "in Lair" or "Wandering", Arneson's method gives you the exact numbers for the size of the encounter. (Same method is used in CoZ btw).
For the sake of completeness here is the bulk of the rest of the paragraph in the FFC (page 25 of the 1980 reprint)
" General Outlines:
*If a group rolls three "6's" in a row, then they are considered to be located in an adjacent hex and not able to return that day.
* If the direction and distance of two groups are identical, then they will be considered to be together. If the direction and distance rolled would place the group in an area where they would conflict with another group (not their own), they will be considered to have returned "home" to report what they found, and be there when the attack hits.
*When more than one camp of the same type of creatures is present in a single hex area, they will be considered to be friendly with each other and of the same tribe. This will not hold true for adjacent hex areas. Thus, if one tribe is attacked, or detects the attacking force, they may aid each other at the Judge's discretion. It is suggested that the Judge generate Character types for the Chieftains involved to determine if they are compatible or not (jealous of each other or very unpopular among their tribe members).
*In the case of some "Loner" type creatures, the presence of two or more areas settled by their kind will not mean that they are allied.
*If two or more groups of creatures of the same race are located in the same area of the hex, they will be considered to be one larger than normal grouping.
*If two or more groups of creatures are located in the same area but are of different races, then they will have to fight it out to see who gets a chance to settle in the area."
There you have it. Notice there is nothing here from Arneson about scaling. Any given hex in his system could be as dangerous as any other given hex.
However, it would be possible for a referee to create a degree of scaling, if desired, by increasing the number of lairs per hex as you get further into the wilderness, increasing the size of the populations, and/or designing and using something like the monster "level tables" in U&WA (p10-11) to increase the chance of tougher monsters the further you get from civilization.