justj,
Just try them. I also am bowel incontinent and experiment with a variety of diapers. Tall internal standing leak guards always are the best choice. However, many diapers without them also perform quite well. Due to my medical situation, I experience several messy diapers a week, so I have some experience with the subject.

Below are a few things to look for:
If diapers lack internal leak guards, it is essential that they have good elastic leg gathers that fit reasonably well.
Crotch width often is a factor. A wider crotch width provides more space to contain fecal matter before it pushes against the leg gathers. Some diapers have croth widths as narrow as 4.5" while a few are as wide as 12." Most males will find a width of 6" or wider to be comfortable as they are wide enough to encompass male genitals.
Good diapers for fecal incontinence have some additional space designed into the rear, sometimes called a “fecal containment zone,” “sag space,” or “drop zone.” This slightly droopy place in the rear of the diaper diaper provides a small amount of space where fecal material can be expelled and contained. This space significantly reduces the likelihood of fecal material being pushed over the internal leak guards and against the leg gathers. Otherwise, upon sitting down there would be a much higher likelihood of a leakage of stool.
Remember your diaper does not need to be "perfect," just "good enough."
Good luck!
--John
(double incontinent)