light distance from bulb (newbie question)

ok i know the basics from distance from 600w to 1000w so say i have my 600w hps 15-18 inches away from the plants thats tied to a scrog net vertically and the screen is a 3x3 4 sided cage with 1 plant per side, so if i put a 600w bare bulb in the middle of the cage minus the thickness of the bulb i would be getting 15-17 inch clearance each side from the bulb, now as daft as the question might sound but does the distance mean its from the bulb to the net where the plant is tied or from the tip of the buds? if its from the tip of the buds id have no buds lol as in total i only have 17 inch top for bud height. forgive me if im being a daft prat lol.

cheers
ash

Should be from bulb to the top of your plants that your measuring. If your cooling is good enough you can get closer, but for the spread your going for your probably at a good height.

so in terms it would be stupid to think i would get these size buds (below) with a 6 x 4 spread at the same time? its because of pics like those i asked this question because those buds look like they are about 12 inches and with me only just having the recommended distance for a 600w id be growing a max height of an inch buds.

Hey reefy just make sure the bulb isn't too hot for the top of your plants, everyones setup is different in terms of heat & ventilation. If you want the bulb closer then add more fans to cool things down. Good luck

hi, i understand the heat and ventilation idea as thats not a problem but what im getting at is if i label each side so there is 4 sides to a cage so A B C D and each side is equal distance from cage to bulb which is 18" so if we start from side A and in flower stage the buds start getting taller towards the bulb so say the bud gets to 6 inches long, thats 6 inches towards the bulb so it will no longer be an 18" distance it will be 12 inches and if i move the bulb futher back it will then make the opposite side which is C a smaller distance so the bare bulb is actually stuck in that one position. so my point is that i will only be able to have 2 inch bud size but even if i have a 6ft by 3ft area of small buds will that be a good yeld like a rough guess of X amount of ounces?

i hope ive explained the way i was hoping to

cheers guys