To answer your question on the the Target Box size in your Huddata.ini scroll down too [Display001]
[Debug]
DisplayDebug=FALSE
TextFontName=Arial
TextSize=16
[smallLabelFont]
TextFontName=Arial
TextSize=12
[HUDLabels]
EnableLabels=TRUE
LabelFriendlyAir=TRUE
LabelFriendlyGround=TRUE
LabelEnemyAir=TRUE
LabelEnemyGround=TRUE
[MapLabels]
EnableLabels=TRUE
LabelFriendlyAir=TRUE
LabelFriendlyGround=TRUE
LabelEnemyAir=TRUE
LabelEnemyGround=TRUE
[infoDisplay]
//BackgroundImage=TextBackground.tga
BottomLeftPosition=0.01,0.985
BottomRightPosition=0.99,0.985
DisplayWidth=0.20
VerticalBorder=0.0015
HorizontalBorder=0.008
EnemyTargetColor=1.0,0.0,0.0,1.0
FriendlyTargetColor=0.0,0.0,1.0,1.0
UnknownTargetColor=1.0,1.0,0.0,1.0
WaypointColor=1.0,1.0,1.0,1.0
TextFile=HUDText.str
NormalColor=1.0,1.0,1.0,1.0
WarningColor1=1.0,1.0,0.0,1.0
WarningColor2=1.0,0.0,0.0,1.0
AGLAltStart=609.6
AGLAltWarning=152.4
[Display001]
DisplayType=DIRECTOR
ObjectType=TARGET_ENEMY
ConeSize=25
BoxSize=10------------------------------------------Change this # lower is smaller
BoxType=SQUARE
BoxColor=1.0,0.0,0.0,0.75
ConeModelName=redcone
[Display002]
DisplayType=DIRECTOR
ObjectType=TARGET_FRIENDLY
ConeSize=25
BoxSize=10--------------------------------------Lower is smaller
BoxType=SQUARE
BoxColor=0.0,0.0,1.0,0.75
ConeModelName=bluecone
[Display003]
DisplayType=DIRECTOR
ObjectType=NEXT_WAYPOINT
ConeSize=25
BoxSize=10------------------------------------lower is smaller
BoxType=TRIANGLE
BoxColor=1.0,1.0,1.0,0.75
ConeModelName=whitecone
[Display004]
//DisplayType=RADAR
PosX=0.865
PosY=0.015
Width=0.125
Height=0.16666667
Alpha=0.60
InitTime=2.0
[Display005]
DisplayType=DIRECTOR
ObjectType=RADAR_TARGET
ConeSize=25
BoxSize=10--------------------------------lowere is smaller
BoxType=DIAMOND
BoxColor=1.0,1.0,0.0,0.75
ConeModelName=
It should apply to the rest of the shapes also in the Displays