750 point Imperial Guard list + magnetizing question

HQ

Lord Commissar

Bolt Pistol, Camo Gear, Carapace Armour, Close Combat Weapon

Troops

Veterans

5x Veterans w/ Lasgun, 2x Veterans w/ Plasma Gun, Autocannon Team

Chimera

Heavy Bolter, Multi-laser

Veterans

, 5x Veterans w/ Lasgun, 2x Veterans w/ Meltagun, Autocannon Team

Chimera

Heavy Bolter, Multi-laser

Fast Attack

Scout Sentinel Squadron

3x Scout Sentinels w/Autocannons, Camo Netting

Heavy Support

Leman Russ Squadron

1x Battle Tank w/2x Heavy Bolter, Camo Netting, Heavy Bolter, Battle Cannon

Comes out to 750 points exactly. I'll probably be doing friendly games against Necrons/ Space Marines.

About magnetizing, are there any specific sizes I should be buying?