Don't bother.

Eh, whatever. It's not worth the effort to make two different strengths, so you just make one big batch of frozen goodness, in a medium strength area.
Soon you all have a solo cup in hand. Riley and Allison are out of the pool on the far side, catching the sun, and Karen is swimming lengths up and down the pool. She really does have an incredible body. {if KarenSFantasy =1} Her bikini is hard pressed to contain every inch of it while she's exerting herself. You swallow, and adjust yourself in your shorts. You{else} You remind yourself that she's your sister-in-law, and{endif} start setting up more lawn chairs in case people want to eat poolside instead of indoors. You know what you prefer.
You drift over to Riley after a little while, and sit on the patio next to her as she luxuriates in the sun.
"I'm so happy to be home, daddy. First year was tough. I have so many stories." she smiles, and rubs your arm. "You're more toned than when I left after Christmas break."
You blush, "Thanks for noticing, Riley. I've been hitting the weight bench a lot." Is the **** going to Riley's head? She's stroking your bicep. You decide to change the subject.
"Do you want to talk about what happened with Matt? I know it's probably awkward, but you know I'm a good listener."
Riley's face slips for a second. But then it's all smiles again. "It's no big deal, Dad. People grow apart..." but her breath catches. Her face contorts for a second. "...he's just a stupid boy, anyway!"
"Oh honey, I'm sorry, I shouldn't have brought it up." You squeeze her hand. "I didn't mean to make you cry." You want to pound Matt into next week right now.
"It's okay, dad." She's sitting up now, and wiping a single tear. "It's just, you know. When you're a little girl, or even in high school, you have this vision in your head. This dream: walking down the aisle, having kids, spending your life together. Since I was 14 it was always Matt in that picture. And...5 months apart was all it took to shatter it into a million pieces. Was it even real for him?" She starts to sniffle again.
"Riley, he's a stupid kid. He doesn't deserve you. If he can throw all that he had with you away like that, then that's his loss, baby. And good riddance, I say! I didn't want to tell you this, but I always thought he was a punk."
"Really? You never let on at all!" Riley looks astonished.
"My baby girl loved him, so I had to be nice."
Another of her big smiles splits her face. She hugs your arm and lays her head against your bicep. "It really is so good to be home. I knew I'd feel better as soon as I pulled in. Thanks, daddy."
"You're welcome baby."
After an extended time, with Riley rubbing your arm and snuggling against your shoulder, you start to get uncomfortable. "Can...I....have my arm back please, angel?"
She lets go with a start, and shakes her head. "Yeah...sorry." Her tits had felt very soft against your arm... you shudder at the vile thought about your own daughter. {If Morality > 40} But you keep on thinking about them, almost against your will. They had grown since last year, your sure of it. They might be bigger than Jenna's now. You'd need a side by side comparison to be sure...{else} You shake it off. {endif}