What is front wheel minimum back spacing?

Greetings to FABO. Hope everyone is well. Many questions were answered on my last two threads but one. What is the minimum back spacing allowed on 68 Barracuda with 73+ disc brake conversion. Received many answers as to what would fit but different wheel and tire combinations were involved without much back spacing information or if provided; did not fit my wheel availability. Thought I would take a different approach. The following are my front wheel options. Question 1: Will I have clearance issues with 205/60-15 on either 15X6 3.25in BS, 15X6 3.75in BS, or 15X7 4in BS. Question 2: Will I have clearance issues with 205/70-14 on either 14X5.5 3.75in BS or 14X6 4in BS. Thanks.