- Look at the moons. Is today a stat day? Consider not doing this at all on stat days.
- Look at your moon sign. All the moon signs (except Bad Moon) now give you +10% to one of the stats. You'll almost certainly need to take that into account.
- Look at your detuned radio or other monster aggravation device. Go turn it off.
- Look at your effects. Are you running Ur-Kel? Shrug it off. Do you have Wasabi Sinuses or Peeled Eyeballs? Those are -1 stats per fight. You may want get rid of those (but see below).
- Look at your equipment. Are you wearing Space Trip safety headphones? Or any other ML-affecting or stats-per-fight equipment? Remove those.

To spade a volleyball: Remove all +ML and +stats per fight effects and equipment. Use Knob Goblin nasal spray to get Wasabi Sinuses for -1 stats per fight. Fight crates in the Noob Cave. They should give you 0 stats per fight, so any stats you receive are volleyball stats. A sombrero could conceivably give you 1 stat here, but most likely it will give 0.

To eliminate variance, try to make your volleyball have a weight which is a perfect square. 25 pounds is nice and easy; you can also go for 36 if you don't want to get rid of Leash (Sympathy, Leash, Empathy and 1 tiny plastic). That way, if the volleyball is acting as you expect, you should get the same stats every fight. Any deviation at all means your hypothesis was incorrect.

Remember that the moon sign bonus rounds up. So let's say you're a muscle class under Mongoose, which has +10% muscle gains. A 25-pound volleyball against crates with Wasabi should give precisely 5 stats. If we get any muscle stats, they will be increased by 1. So, 5/1/0 is consistent with our 25-pound VB hypothesis (5 stats -> 4/1/0 increased to 5/1/0 by moon sign). But 0/3/3 is not (it's 6 stats).

Example: Scarecrow with hobo dungarees at 36 pounds, under Mongoose: we get the results 5/0/0 4/1/0 2/3/0 2/2/1 3/2/1. Removing the moon sign bonus, we get stat totals of 4 4 4 4 5. This means the VB is > 16 pounds and < 25 pounds. Most likely it's 18 pounds (half-weight VB). We could raise the familiar weight to 50 pounds to test the half-weight hypothesis more fully (expected output then would be 5 5 5 5 5 5 ...).

To spade a sombrero: First determine whether it actually is a sombrero and not a volleyball. The best way to do that is to fight a low-level monster and a high-level monster, and see if the bonus stats from the familiar are consistent. If they are, then it's a volleyball. If they are not, then it's a sombrero.

Fighting high-level monsters involves compensating for the moon sign variance. We'll need more data points because of this. What we want to determine is the total stats from the familiar, after removing the stats from the monster itself. Therefore we note all 3 substat components, divide each one to knock out the moon variance, and subtract the monster's natural stat reward. There is some variance involved in this, so do it several times to eliminate outliers.

For example, suppose we fight a frat cave boy (nominally 235 attack) with Wasabi Sinuses as a muscle class under Moongoose on a Myst day, and get 47/12/16 substats. The 47 is 10% higher due to Mongoose, and the 12 is 25% higher due to Myst day. So the stats we really got, before the moons, were approximately 47/1.1 + 12/1.25 + 16 =~ 68.3 substats. The monster's native reward, minus 1 for Wasabi, is 235/4 - 1 = 57.75. Therefore, the familiar gave approximately 10.6 substats, with a large margin of error. Repeating this several times and averaging the results will help pinpoint the actual values. In this case, we may wish to wait until it's no longer a Myst day, to remove one source of variance.