Thanks , so for the wire fit I think I need to go xt150 just because the esc wires just make it. Rather than worry about the connection failing, I'll go for the piece of mind and cost is ok at 10$ for the 5pairs so I ordered 2 packs from HK.
I'll set up the 2 new batteries with the xt150 and maybe swap out the ec5's on 2 other packs so I can have 2 flight ready set ups.
I'll leave the other ec5 on my esc's in the 500's (at least for now) and maybe just build a small jumper xt150 - ec5 for charging and will also allow me to use them if push comes to shove. Although that extra connection between lipo and esc is not ideal.. I really don't fly hard enough to over stress anything heat wise.