If there's no fletching contact and spine is correct it looks to me like the montecs are probably hitting low. The montecs have a higher surface area, which makes them more likely to plane if your bow isn't tuned. Where do your field points hit compared to both heads? If field points hit above your montecs try bumping up your rest up in 1/32" increments, and if there's no other issues like spine or contact then I almost guarantee you can get the shuttles, field points and montecs hitting together, or at least very close. Look up broad head tuning, probably needs to be done with your bow. Also make sure both those broadheads weigh the same.
Shuttle t's are probably the best flying fixed head on the market.
