Our LF transformers are 7 layer, PSPSPSP, the output winding is 65V, 600uH, 200nH Lleak, all referred to sec (LV) this is 0.033% leakage (0.0167% if just the LV leak counted).
It would not be hard to generate a 100nH LV Llk Tx which is all you would need for 75A out
Remember once the current has swung in the o/p winding to +/-75A, it sits there increasing slowly due to the o/p choke, or driving voltage, so simply calculating the XL of the leakage referred to the o/p is not the whole story, the vector of the XL drop is 90 degrees out of phase with the IR drop in the secondary, so they don't add scalarly, but vectorially,
So 6.7milli ohm on the sec for 75A gives 0.5Vac drop, 100nH @100kHz, gives XL=0.0628 ohm (4.7V at 75A) which is not so bad as all it requires is a slightly higher driving voltage on the HV side, in the case of a centre tapped 2 diode o/p very few extra volts would need to be found on the HV side...