My GDP photo fems grow is producing really nice buds at the top of the plants. Is it it possible to cut off the top buds when ripe and then to continue grow the bottom part of plant until those are farther along? Will bottom buds mature, ripen and get bigger?
Yes you can do a partial harvest on the upper buds. I just finished one and did 3 separate harvestings. The last and lowest buds we’re mainly for oils or edibles 
You can, but I’ve never felt it was worth it.
Why is that Grow Bro, why not give the lower fruit some more time to ripen? I get it if the lower buds are popcorn or larfe but larger mid buds can give you some great smoke and buzz
Like stated you can do a partial harvest. Usually it doesn’t help much in yield.
FYI your plant still has some time to go: two weeks? Three?
Yield doesn’t improve much for time and resources needed.
Being a photo, you can harvest (when it’s ready 
) then re-veg and do it all over again.
Fine looking plants 