"Should I use the 5498 box 1 and box 4 numbers to accurately document box 1 on 8606?"
Probably not quite. The amount in box 4 represents the gain/loss adjusted amount transferred to the traditional IRA, not the amount of contribution recharacterized. You would need to look at the Form 5498 from the Roth IRA to see how much the original contribution to the Roth IRA was. If that entire Roth IRA contribution was recharacterized, the amount of traditional IRA contributions was the sum of the contribution amounts from both of these Forms 5498.
