I'm putting in a basement bath, connecting with a 4" cast iron main that is in excellent condition.

1) Before installation, the city inspector told me we need a directional Wye fitting there. He hasn't been back yet since the installation. My plumber installed a 4 x 4 Fernco Qwik-tee. The quick tee ties the new PVC drain at a right angle and not a Y angle. I suppose the inspector will tell me if this qualifies as a directional fitting. But in the meanwhile, can one of the gurus here tell me the answer please.

2) My plumber put in a 4" PVC drain from the new toilet. Bigger is better right? Good flow and less risk of stoppage, right? Any downsides?

Thanks in advance.

In my neck of the woods you cannot connect a horizontal pipe using a TEE fitting... further, you cannot use a fernco tee either. I suggest you call your inspector and ask him if fernco type fitting are allowed underground in your area.

YOU can use a combination wye and 1/8th bend fitting... called a TY fitting... but that does not sound like what you described (a combination fittting like this looks like a wye fitting with a 45 degree angle added to square it up for staright run).

And 4" is fine for a toilet.

Let me know if this helped!

1) Before installation, the city inspector told me we need a directional Wye fitting there. He hasn't been back yet since the installation. My plumber installed a 4 x 4 Fernco Qwik-tee. The quick tee ties the new PVC drain at a right angle and not a Y angle. I suppose the inspector will tell me if this qualifies as a directional fitting. But in the meanwhile, can one of the gurus here tell me the answer please.
Listen to Massplumber! Your plumber will be instructed by the inspector to change that Fernco Tee to a combination wye and eighth bend. All plumbing codes forbid using sanitary tees under the slab.

2) My plumber put in a 4" PVC drain from the new toilet. Bigger is better right? Good flow and less risk of stoppage, right? Any downsides?

Again, Massplumber's bang on. We mandate a 4" toilet drain under our slabs. Regards, Tom

Bigger is not always better. A 4 inch will drain better and it was used forever, but it will not allow the draining to scour the pipe. I use 3 inch and a 4 inch riser. You can legally use more than one toilet on a 3 inch system.