My advice is this...
Because you are using less light, your plants will gain more from max lumens, than from ideal spectrum.
Put more lux on the leaves. Your plants want brightness more than anything in flower.
Get the brightest bulbs your system can handle, and never lower your lumens. Maybe even try to add more light. Some folks say you should double your watts from veg to bloom, but again, you're not growing in an ideal environment, so max out what you can.