TMNT #1 2nd print does have a decent value but nowhere near the 1st of course. The first print had around 3000-3250 print run, whereas the second was 15,000 if I remember correctly (3rd was around 35,000). The only magazine size issues were #1 (1st, 2nd & 3rd prints), #2 (1st & 2nd prints), #3 & 4 (1st prints only). These must be submitted as magazine size to CGC. Then #5 began the regular comic size as you noted. For values look at Ebay sold listings sorted most recent sales first, that's the best and easiest way to find true market value.