When applying veneer glue, the rule of thumb is that the surface of the substrate should look "evenly painted" with veneer glue. A dedicated glue roller like this works best.
Glue spreaders - MarMasz - Woodworking Machines
Roller Coater Glue Spreaders
Hand-Held Veneer Glue Applicator with Hopper: $68.20
Glue Applicator Roller Portable Adjustable Coated Glue Roller
Pfohl 150 - with ribbed poreless roller for PVA / Urea
Roller Coater Glue Spreaders
Glue Applicators veneer equipment/supplies
Double Sided Veneer Glue Applicator - INNOVATOR Machinery
Glue it with these glue rollers that lay down the perfect amount of glue for skateboard building or veneering.
Glue Roller 3
Stuck like glue
Acogedor 6 inch Adjustable Glue applicator, Portable Coated Glue
Glue spreaders - MarMasz - Woodworking Machines
Amy Roke - Glue / Adhesive Spreaders
Woodworking Machine Double Side Z Type Glue Spreader Roller
7 Glue Spreader with Hopper - Vacuum Pressing Systems