The best advice I can give is to use a split, or "tweezer" style torsion tool.
I've taken photos of my SoutOrd tool as an example. This style of torsion
tool places a more uniform distribution of tension to the plug and shouldn't
get in the way of your picking tool nearly as much. Sorry for the size of some
of these images, but my computer has recently become allergic to Photoshop.



Since you're asking how to make one from flat steel here's a hastily assembled
tutorial using a ribbon of printer paper. Sorry, but I don't have any flat steel or
wiper inserts to show you a more proper and effective tool that I can test, but
this ought to give you the right idea. The tools you'll need are pliers or similar
tool that you can use to bend the steel you have on hand, and for making the
cuts in the steel I like to use a triangular file as they are rigid and easy to work
with. Also if you have a vice that can help a lot also.
Start with your strip of steel. I've only used a ribbon of paper about 11cm long
but I recommend you use a piece about 14cm to 16cm long if you have one
(or any length you feel most comfortable with).

Start by making a bend at halfway along the steel, but don't bend it flat just yet
(or at all).

After you've made your bend, mark a point about halfway from your first bend
to the end of the steel piece. This will be where you twist the steel piece 90
degrees on each end of your steel. You don't have to use a twisting bend here
but the alternative is a lot of grinding or filing to shape your steel in to the pronged
shape like the SouthOrd tool and will take more time (and I'm using the tools I have
on hand also).

Obviously paper isn't quite as workable as steel is so I've folded it to show you
the desired result of the twisting bend in the steel.

What you end up with is a sort of fork shape. From this point, make another
mark or just make a short bend at the end of the steel. About a 5mm bend
should work nicely.


After you've completed the bend on both ends of your steel, you'll need your
file, dremel tool, or any kind of grinder that will get you the prongs on the end
of your tool. These prongs should only be around 1.5mm to 2.5mm thick but use
your own discretion for what you need. Keep working at it until you get the
shape you need.

Once you've completed this step, you should end up with a completed tool
that looks very much like this (only not made from printer paper)

If the steel you're working with is strong enough, you ought to be able to use
your new tool in exactly the same way as the SouthOrd tool I've used as an example


I really hate providing instructions for a tool that I haven't been able to make
and test myself, but like I said, I don't have any flat steel in stock to try it out.
However this ought to work well in theory, and will replicate, or at least mimic,
how the professionally made tool works.
If you do make this, let me know how it goes. The next trip I make to the garage
I'll be sure to pick up some steel and get to work on a more proper tutorial, assuming this works.
Good Luck!