budget cob

Hello everyone! I was looking to buy led to replace my 400w hps so i could get healthier leaves and, i don't really need to be able to pull 200g on average I was wondering, how many led do i need to get at least 5 oz or a tad lower( 120-150 grams) But all i have read was related to space instead...

Looking for preferably a cob setup to veg and maintain a mother plant and grow 1 auto at a time. I've done a little research and grasp the basics of drivers and what not but not all that techy. I want to get my feet wet and keep cost low as well. Shipping is high but the parts are fairly priced...