I'm going to try to test out VR weapon lengths as they apply to close combat attacks. Effectively they vary with each individual attack's animation so I will try to measure each attack's length individually. If we measure enough attacks it may eventually be possible to guess a weapon's true innate length, if we combine a knowledge of body sizes and arm lengths from other threads.
It's too difficult and complex to test the side coverage areas of normal CC so I will just be measuring the frontal length for each attack. Since normal CC slides forward, I'll instead do circle CC to get rid of most of the forward slide motion and record the maximum distance for which an attack hits reliably. I'll write both the distance before I input the attack, and just as the attack is about to hit the enemy. For dash CC different methods have to be employed, but I think I can roughly measure the length of attacks in the side and diagonal directions.
I'm going to start out testing Kagekiyo "Forest" and Kagekiyo "Mountain" and compare the results. They are the spear and staff Kagekiyos. Zaarock said he thinks the spear is longer than the staff. Since their close combat attack animations are identical we should be able to test that pretty well. The punching bag will be Vox "Dan" since he has a fairly symmetrical body.
Kagekiyo "Forest"
left/right circle LW
58, 44
left circle CW (1st hit)
56, 43
right circle CW (1st hit)
57, 44
left/right circle CW (2nd hit)
58, 45
left/right circle RW
54, 41
left circle TLW (1st hit)
53, 39
right circle TLW (1st hit)
52, 38
left/right circle TLW (final hit)
58, 44
left circle TCW
59, 46
right circle TCW
60, 47
left/right circle TRW
51, 38
jumping CC
39
dash CC LW (left side)
39
dash CC LW (diagonal)
43
dash CC LW (forward)
48
dash CC RW (right side)
42
dash CC RW (diagonal)
43
dash CC RW (forward)
46
dash CC CW
44
Kagekiyo "Mountain"
left/right circle LW
58, 44
left circle CW (1st hit)
55, 43
right circle CW (1st hit)
56, 44
left/right circle CW (2nd hit)
58, 45
left circle RW
54, 41
right circle RW
53, 40
left/right circle TLW (1st hit)
52, 38
left/right circle TLW (final hit)
58, 44
left circle TCW
58, 46
right circle TCW
59, 47
left/right circle TRW
50, 37
jumping CC
39
dash CC LW (left side)
39
dash CC LW (diagonal)
43
dash CC LW (forward)
48
dash CC RW (right side)
41
dash CC RW (diagonal)
43
dash CC RW (forward)
46
dash CC CW
44
The distance readouts are rounded to the nearest whole unit even though the game thinks more accurately. Plus some of the tests are crude, so it's not necessary to worry about minor discrepancies. Overall this does suggest that the spear is longer than the staff, but only by a distance of 0.5 or so, which is pretty small, just a few pixels. In comparison with the total length of the weapon, that's roughly 1% longer.