Just be very careful since the color of your leads is your only means of "Reverse Polarity Protection". You could go "male-female" on one side, and then do the same on the other side. This way they can't be plugged in backwards.

When I solder Bullet connectors, I always tin the wire first with alot of solder. Once it's tinned all the way around, remove the heat and continue to lay solder on it. Create a "bulb" of solder there.

Then I insert the connector into a clamp on a "helping hands" and fill the connector to the bottom edge of the hole you mentioned. A little always runs out that I have to clean up when I put the wire in.

With heat applied to the connector, the tinned wire will heat up and slide right in.

On the larger connectors, I've noticed they don't fill all the way to the top like 3mm connectors do. I think it's OK if they don't. Just so you have a contact patch a little larger than the Cross Section of the wire, it should be fine. :yes:

Yes i do exactly what you did, but i've find a way to fill the connector. I take a pair of Vise Grip plier and install the plier for they "obture" the hole of the connector. Like that, i can fill the connector without any problem. After that, i remove the plier and just clean the connector with a Dremel and a sending pad to remove any remaining tin (or solder, don't know the real word in english:intello:)

And yes, i use female on red batterie and black ESC and male on black batterie and red ESC.

Deans for me too. I have no trouble gripping the connector, except when it is really cold out. It would be nice if Deans had an option for the same connector except with a sightly longer grip area.

Also, a lot of people at the track seem to use Deans as well, so it may be easier to find someone to lend you a pack to use if needed...

Deans Ultra here, and not the knockoff type. While the fakes might have better contact and are much cheaper, they are near impossible to disconnect. The real ones are pretty easy to unplug as long as they don't get deformed while soldering.

If I were to try something else it would be the traxxas connectors or 5/6mm bullet plugs. Like others, I don't want to swap all of my stuff nor pay for all new connectors.