Short answer is I wouldn't do it.  What discharge rating are the cells in question?  You are kinda missing a lot of important cell performance parameters in your question.  Best to keep everything the same brand/type/rating.

Thanks
I was thinking along the lines of not doing it for flying packs anyway. These were pulled out from some laptop batteries that were not being used. Just as well, one cell was so hot after charging on the laptop I had to throw that battery out any way. These batteries will serve their purpose as practice for building packs for some 4&6s Packs that will be used for flying. I plan to spot weld as much as I can and the rest will have to be soldered.

Thanks Again
Darrell.