I applaud your desire to do power electronics the hard way. Meaning with SCRs.
The only three phase SCR bridges I built in the early 80s were all naturally commutated. Force commutated bridges I only built single phase, and they are tricky.
My recommendations, based on a lot of sweat and tears (and some nasty explosions):
-SCRs are commutated by having its current decrease to zero. This means that the LC tank, pilot SCR or whatever you are using to force commutate the device, has to be able to provide the full load current magnitude, for the turnoff period.
-For reliable commutation, you have to use inverter grade SCRs. Regular phase control SCRs have widely variable commutation times. Back then, I would only use SCRs from Semikron.
-The commutating capacitors will see extremely large dI/dt pulses. Regular capacitors tend to fail prematurely. Back then General Electric made some oil filled caps suitable for inverter purposes.
-Fuse each SCR individually, THIS IS A MUST, with a fuse capable of quenching large fault currents. You want to limit the damage when a SCR fails or misfires.
-The gate driver should be very robust, and provide good insulation. Back then Coilcraft had some excellent SCR gate drive transformers.
-Speaking of gate drive, use a picket fence waveform. Don't ever rely on a single pulse for the SCR to latch.