i'm using this: (aron's crosshairswitcher)
alias aslot1 "slot1;cl_crosshair_file crosshair7;cl_crosshair_scale 32;cl_crosshair_red 0;cl_crosshair_green 255;cl_crosshair_blue 0;r_drawviewmodel 0;viewmodel_fov 95;MW1"
alias aslot2 "slot2;cl_crosshair_file crosshair5;cl_crosshair_scale 32;cl_crosshair_red 0;cl_crosshair_green 255;cl_crosshair_blue 0;r_drawviewmodel 0;viewmodel_fov 20;MW2"
alias aslot3 "slot3;cl_crosshair_file crosshair7;cl_crosshair_scale 32;cl_crosshair_red 0;cl_crosshair_green 255;cl_crosshair_blue 0;r_drawviewmodel 1;viewmodel_fov 110;MW3"
alias Q1 "aslot2"
alias Q2 "aslot1"
alias MW1 "bind mwheelup aslot3;bind mwheeldown aslot2;bind q Q1"
alias MW2 "bind mwheelup aslot1;bind mwheeldown aslot3;bind q Q2"
alias MW3 "bind mwheelup aslot2;bind mwheeldown aslot1"
bind 1 aslot1
bind 2 aslot2
bind 3 aslot3
bind 4 slot4
bind 5 slot5
aslot1
you can change crosshairs, viewmodels, works with 1-3 buttons and with mouse wheel