I am tying into a 3' floor drain with PVC(underground). I have three questions.

1. Should I use a shielded or non shielded connector?
My thoughts were to use shielded so that the rubber would not get punctured.

2. The actuall fitting I was thinking to use was a sweaping 90 but I may have space issues.
So I also have a regular 90 just in case.
If there are no space issues which should I use?
Thoughts were that sweaping 90 would be less likely to cause clogs.

3. To cut said cast iron would it be better to use a sawzall or a snap cutter? I think that is what its called.
I heard there is a risk of crushing the cast with the snap cutter.

Let me take this one at a time.

1. Should I use a shielded or non shielded connector? We use shielded couplings underground.

2. The actuall fitting I was thinking to use was a sweaping 90 but I may have space issues.
So I also have a regular 90 just in case. If there are no space issues which should I use? Thoughts were that sweaping 90 would be less likely to cause clogs.
And you're 100% correct. The more angle on the bend the less chance of a clogg.

3. To cut said cast iron would it be better to use a sawzall or a snap cutter? I think that is what its called. I heard there is a risk of crushing the cast with the snap cutter.
If you're not familiar with a snap or ratchet cutter the possibility exists that you can crush the pipe. Cast iron's very hard so have plenty of metal blades handy if you use a Saws-All. Good luck, Tom