From what I have seen and heard it seems like .5-1 gram per watt dried is the realistic goal for most. That's 500-1000g with your light. With 4 10 gal buckets in your space and with a 1k light, if you really want an estimate to look forward to, I would say just under to just over 1 pound. Like the others said, you can dial a strain in and get a more even canopy and larger yields as you gain knowledge on the specific needs of individual strains you work with. Per plant if all 4 plants bush out and fill the tent pretty well and have proper support for the weight of the flowers, you could get 4-8oz a plant on average. There could be freakishly high or low yielding strains or phenotypes, but I have yet to find either, and average 6-8oz a plant most recently. 1000g per light seems to be the ideal yield when a strain is dialed in and a high yielder, and most folks I know average in the 1-1.5pound area.
Don't over do or under do nutes by too much, do let the plants dry out between waterings, maybe look up and try out some compost tea to introduce beneficial microbes, keep temp and humidity in check and have some decent ventilation, and you should have little or no problem hitting a p even with 4 different strains. Definitely take clones so you can decide which strain(s) you like best and continue to grow it/them. If yield is the main concern then grow out clones of the best yielding of the 4 and continue to take notes and make adjustments and you that's when you might close in on 2p per 1k light. Don't worry too much about yield, and do enjoy time caring for your plants. With good equipment, quality genetics, basic knowledge, and help from more knowledgeable friends, you will do well. Couldn't agree more with the terms less is more and keep it simple. Reading around the forums will be the quickest way to learn and answer questions for yourself you may have.