Technical Can any of you suspension gurus offer some anti-squat advice?

It is mainly for "roll steer" which is to control wheelbase variations.
Most of the load on the tyres is when the suspension is under compression ,not extension [or droop]

So if you allow 2" of compression, the lower arm arcs outwards [lengthening wheelbase] for the 1st inch of travel, then arcs inwards back to original wheelbase for the 2nd inch of travel.
The lower arm p***es through a horizontal line

Pointing the arms upwards is good for anti-squat and forward bite [this is popular in dirt modifieds]
BUT the car becomes very unstable ,needing constant driver correction on uneven surfaces.[OK on the dirt track]
Many drivers mistake this twitchiness with front end alignment.

Roll understeer promotes rear side bite mid corner [so you can get on the gas early and throttle oversteer a car]
Too much Roll understeer can feel twitchy but you can actually take your hand off the wheel and it will eventually self correct.

A lot of single axle trailers that sway are caused buy roll oversteer [usually the curvature of the leaf springs]

 

If I am following correctly, your lower arm with the front an inch higher, actually starts out in an "oversteer" condition at ride height. Then as it is compressed the full two inches, it ends up in "understeer".

It is as close to a neutral setup as you can get in regards to under/oversteer?

Why/what causes the rear suspension to compress though if it is at ride height? Is it setup this way so it doesn't become too twitchy in the situation that you hit a bump ?

 

a 24" long arm only arcs 0.020" each side of horizontal

1st inch ......slight oversteer
2nd inch ....neutral
3rd inch .....slight understeer [this is when the tyres are really loaded]

If a 24" arm was set up horizontal it would arc [understeer] 0.090 with 3" compression.

Yes it's for going over "raised" bumps on uneven surfaces .

So this set up is what you want for driver /p***enger comfort.

 

There are suspension setups, that create close to neutral squat value. Seems I recall, planning a line- of- action, that p***es thru the center of m***, of the completed car 'weight'. Aim above this may bring squat, below, may bring lift.

 

Best anti-squat advice I can give is "don't squat with your spurs on"