Introducing Leopard Geckos

I am the proud owner of two female leopard geckos. One is around 4 years old and is a normal morph, Geaky and slightly larger than the second one a year old tangerine carrot tail, Chuckles. When I first brought home the tangerine she was in pretty bad shape, I got her from Petco for $10.00 apparently someone dropped off around 15 junvile leopard geckos all different morphs. They were all in the same small inclosure and they were trying to get rid of them, since they were unsexed and I am sure there were some males in the bunch.
Well back to my problem Figuring Geaky would be fine with Chuckles since she had had a tank mate, fellow hatchling, for the past 3 years until my other died of an unexpectly. But when I placed the new tangerine in Geaky went into cat hunting mood but I grabbed Chuckles out before anything could happen. There are now in separate tanks and Chuckles had turned a leaf for the better and is quite a beautiful leo. I would like to re introduce the two, since Chuckles is now full grown and healthy.
My friend who owns a colony of female leos told me if I rearrange the "furnature" and make the tank completely different arrange and then place them both in. I dont know how accurate this is and would like some help in any other tips or suggestions.
Thanks...

I would suggest completely cleaning and re-arranging the enclosure and furniture items you plan to house them in together... this way, neither will feel 'territorial' in a new environment. Watch carefuly for signs of aggression.

Thanks,
Yes I did just that I put them both into the bigger tank. My older one was just fine and showed no signs of aggression and neither did the younger one. But what I didnt add in the first post was that I did put a divider in the tank so the two could see eachother about a week or so after I purchased the younger one, Chuckles. But Chuckles had somehow managed to climb the divider and I found her there, Geaky was fine with her, but she did have a cut on her back. I took her out and put her in her own tank because the poor little thing was terrified.
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But I guess even though she is almost bigger than Geaky now, she still has the memories and was absolutly scared to death in the tank. She stayed in the cave and when Geaky came in she lowered her head closed her eyes and was actually shivering. So apparently these two werent meant to be tank buds. I guess that means no blizzard . My mom would never allow me to have 3 tanks in my room....

Thanks again for your help much appreicated!