Hi, SN,
Depending on the model, you might get away with an alternative.
If the model(s) are profiles, you could get away with wire hooks through the body and rubber bands. Just bend an open rectangle with legs long enough to go through from inside to outside, and bend hooks. Rubber band-lash the tank(s) on. A problem - your tanks might need to shift up or down as much as a quarter inch to find where the engine runs the same both ways. (Most of us didn't know about this, back in the '50s, and cussed at the engines for not running right.... Didn't use pressure, except for Combat. That was mostly pen bladders or even pacifiers (!) and gave a lot of pressure - which was a problem of its own.)

Could make the wires wider apart than the tank, and use scrap wood shims to vary the height.

Tanks rubber banded on didn't seem to suffer as much from engine vibration as hard-mounted tanks, btw.

Otherwise, soldering tabs on does work. If you need to shift the tank up or down, you might be able to file the tab's slots a bit in the direction you want. (If it goes richer inverted than upright, then the tank is relatively too low. I.e., it's a bit lean upright, fuel must be drawn "uphill", and flipping over to inverted locates the tank "high" so fuel pours "downhill" to the NVA.)
LUCK, and enjoy!!
\LOU