haha, where are you based, I may take them haha
Im not too sure what you should feed guppies as a treat as I dont keep them, but by the sounds of things, if they love the Hikari micro pellets, just use those. Perhaps look into what Human food they can eat and try that as a treat?? (it would have to be boiled to a soft almost mush type food)
I tend to feed my fish every two days, and I never give them any more then they can eat within a three-four minute period, or they will eat everything and end up fat and unhealthy, and even then, I only feed them a very small pinch at a time and when that has gone, ill give them another pinch...this way you keep the wastage down, and the ammonia (as the uneaten food rots, it creates ammonia which can kill your fish), so its important that you remove any uneaten food (especially bloodworms!). This method also means you save a bit of money as you're not wasting any food, your packet will last longer!!!!