Was putting this together for someone else too and figured id share it here. Total cost is $560 plus maybe a few bucks for mouser shipping.
640w total light and the exact same components that come in the HLG kits.
6x V1 4x 3000k 2x 4000k boards - $180
Ultra High Efficiency LED Boards for DIY. QB288 has 288pcs Samsung 561C for 5000K or Lumileds 2835HE for 3000K
horticulturelightinggroup.com
2x triple heatsink (predrilled with screws included) - $140
Pre drilled heatsink for QB304 Quantum Board
horticulturelightinggroup.com
2x hlg320h-c2100 drivers - $170
HLG-320H-C2100 price and availability by authorized and independent electronic component distributors.
www.findchips.com
18awg solid copper hookup wire $15 each color
Shaxon SO18-100BK Solid Copper Wire on Spool, 100-Feet, Black - - Amazon.com
www.amazon.com
1 power cord - you can wire 2x 320w drivers with one or use cheaper 18awg ones for each light $15
Buy 14 AWG 3 Conductor 3-Prong Flat Plug Power Cord with Open Wiring, 15 Amp Max, 6 ft Replacement Power Cord with Open End, Pigtail Open Cable: Everything Else - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
wire splice $6.50
10 pack wago connectors $7.50
Buy Wago 222-412 LEVER-NUTS 2 Conductor Compact Connectors 10 PK: Multiconductor Cables - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
wire basket hangers $10.00