The 9-turn coil will probably get reduced to 4 or 5 turns. The 5-50pf trimmer cap will be too small, even with the 56pf disc cap in parallel with it. Adding a 47pf or 56 pf cap one at a time in parallel will let you "step" up in capacitance roughly equal to the control's adjustment range. Odds are you'll end up with a total parallel capacitance around 200 pf. A trimmer with a higher capacitance range would accomplish the same thing with fewer parts.
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