Watermelon & Pumpkin?

My experience so far is that with the oversized seeds, if you take care of them (weeding, watering, spraying for bugs) but don't "encourage growth" or use fertilizer, you will get four small but decent quality vegetables. If you take care of them and use only the regular vitality fertilizer and don't encourage growth, you will get the two medium sized plants. If you take care of them, use the super vitality fertilizer, and encourage growth whenever you have the option, you will generally get a good (sometimes even perfect) quality oversized plant. That's not a guarantee it will work out like that, but that's how it's gone for me.