for what purpose ? Attack, defense or farming ?
100 spears gives you
1,000 Offense; 1,500 Defense; 2,500 Carry - so good for farming
30 Swords gives you
750 Offense; 1,500 Defense; 450 Carry - good for defense
20 LCs gives you
1,600 Offense; 600 Defense; 1,600 Carry - so good for offensive farming
30 swords and 20 LCs gives you
2,350 Offense; 2,100 Defense; 1,600 Carry - but the LC who are normally twice as fast as the Swords will be held up so you lose some of the advantage of their speed.
Looks on paper that if you're intent on farming nearby dormant villages or other easy-pickings, the 100 spears give you the best carry.
BUT the LC is twice as fast, so send them off without the Swords to slow them down, and their haul will be 3,200 in the same time as the 100 spears carry 2,500