Pasted from the old mIRC.ini Unleashed helpfile.

main=240,1440,74,891,2,1,0

2:
This value describes how the window will be opened:
Values:
2 = Maximize
1 = Minimize
0 = Normal

1:
This value describes if the window should be placed on desktop:
Values:
1 = On
0 = Off

0:
This value describes if the window should be placed on top of all windows.
Values:
1 = On
0 = Off
Only active if Desktop is set (see above)