Rob:
The set-up you described will work just fine. In fact I woud suggest looking at somewhat smaller batteries. I have a 1/2A Pathfinder & a Wee Duper Zilch (same size range as the Jr Lightning Streak) that fly great with the set-up like what you described except I use 1000 mah out of a 1300 battery The smaller battery saves something like 1.5 oz which will be 10% of your probable the RTF weight of around 15 oz.
For a hotter set-up, I also have a Jr Flite Streak that I "motored up" to use an 8x6EP prop and 3Sx1800. It scoots along at 3.8 seconds/lap on .012 x 50' lines - like a Flite Streak should! This one is 15.8oz. Several folks flew this at the 2014 Brodak Fly-in and it produced instant smiles...
Prop: APC 8x6EP
Motor: Arrowind 2215 kv=1180
ESC : Arrowind 18A
Pack: 3Sx1800