This is just my opinion, scope shots are not going to help any one that still has no clue how to impedance match the circuit. Show me one person that understands it yet. All I see is people wanting to see proof, then the same people after showing them proof will be the same ones that come back and say how do you do this and that.
Ronnie has given us a foundation with the DC impedance matching and it looks to me like no one has done their homework as Russ suggested we will need to do.
Seriously, did anyone spend a few hours playing with the spreadsheet I posted? If you did you will realize several things straight away. If you mess with the turns ratio, you're hosed. If you mess with the resistance on the primary side, you're hosed. If you mess with the resistance on the secondary side, you're hosed. If you add or subtract turns someplace you better balance it or... You're hosed.
So what's left to adjust?
Do you see anywhere on that spreadsheet frequency? No you don't.
How about core parameters? Nothing there either.
If you adjust the voltage when the VIC is matched, what do you see? You see the power-out still equals power-in and everything stays matched.
So we have three completely independent variables left we can adjust that will match the VIC to the cell. And the core just needs to be fairly high permeability so we don't have stray flux all over the place. That leaves two variables. Ronnie already stated to start at low voltage and tune the frequency a little at a time, then go to a slightly higher voltage and tune again. Keep doing this until you hit the 12 volts max. No magic there. Once you get up to the 12 volts, don't make any frequency adjustments or you'll fry your VIC.
Come on guys, quit bickering about needing fancy test equipment, scope shots and visual proof. The math is right there staring you in the face.
Do the homework and lets get building or rebuilding if you already screwed up.
Look at your core, figure out what wire to use, make some bobbins starting with the primary, shoot for a 1 : 6 turns ratio, plug in the numbers and try to get as close as you can. The magic is in how this thing really does what Ronnie says it does, not in building it. Ronnie has given us enough to solve that part if we get serious and crunch some numbers. That's my take on it anyway. If Ronnie has more to add that will improve this process, I'm sure he will tell us.
M@