Hey there.
You can change the size of your crosshair by going into hudlayout.res and getting the font of your crosshair.
KonrWings24
{
"controlName" "CExLabel"
"fieldName" "KonrWings20"
"visible" "0"
"enabled" "0"
"zpos" "2"
"xpos" "c-29"
"ypos" "c-24"
"wide" "49"
"tall" "49"
"font" "CrossHairKonrWings"
"labelText" "Z"
"textAlignment" "center"
"fgcolor" "255 255 255 255"
}
Here, for example, the font you're looking for is "CrosshairKonrWings". Go into resource/clientscheme.res and search that font.
"CrossHairKonrWings"
{
"1"
{
"name" "Garm3nFont"
"tall" "18"
"weight" "0"
"antialias" "1"
}
}
Then, just play around with the tall value to make it bigger or smaller. Keep in mind that hud_reloadscheme won't work with any modifications in clientscheme.res, to make it effective you must restart the game.
To change the colour of damage numbers, go into resource/ui/HudDamageAccount.res. "PositiveColor" corresponds to the heal numbers and "NegativeColor" to the damage numbers. Change it to your liking.
Your "minigame" makes me think about MightyMe and his way to train his juggling with pipes. His method was using SourceMod to get full health every 2 seconds and last time I tried installing it and using it, it was broken, so can't help you there. :/