when is the best time to add another light for bud boost?

I have a heat issue atm when i use two lamps which cant be resolved due to surroundings, so therefore ive been growing and into 4 weeks of budding with just one 600w hps. When will be the best time to add the other lamp to boost em? Will it be effective or will it stress the buds too much? The buds are filling out nicely so will it be more beneficial to add the lamp or will it have a negative impact? The area ive got is a bit too big for my adjustawing to cover so really would like to add the second one but it raises the temps on average from 26 celcius to about 36 celcius! Thoughts on this are very welcome thankyou....

You dont want to add more lights at the end of the plants life, think nature where it gets duller at the end of its life.

More/stronger lights will increase bud growth. There is no downside to increasing your lumens at any stage of growing except with sensitive brand new seedlings. Let 'er rip!

Good luck, BigSteve.

yeah I usually add side lighting at the beginning of flowering