I looked around for this and had a hard time finding it.

tell application "Terminal"
	set myTab to do script "cd /some/path && run command one"
	tell (first window whose selected tab is myTab)
		set the position to {0, 0}
		set the number of columns to 80
		set the number of rows to 24
	end tell
	set myTab to do script "cd /some/path && run command two"
	tell (first window whose selected tab is myTab)
		set the position to {570, 10}
		set the number of columns to 80
		set the number of rows to 24
	end tell
	set myTab to do script "cd /some/path && run command three"
	tell (first window whose selected tab is myTab)
		set the position to {0, 390}
		set the number of columns to 80
		set the number of rows to 24
	end tell
	set myTab to do script "cd /some/path && run command four"
	tell (first window whose selected tab is myTab)
		set the position to {570, 390}
		set the number of columns to 80
		set the number of rows to 24
	end tell
end tell