There seems to be a lot of variance, and discussion, as to which minor to open. Some open "better minor" regardless. Some promise four to open 1D, thus opening 1C with 3+ except if 4432, and always opening 1C when 3-3 in the minors. Some open 1D with 4+ except when 4432, thus opening 1C whenever 3-3 in the minors.
Those \are the major options.
In Montreal Relay+, and some other systems, 1D promises 5+ diamonds, such that 1C is opened with a rare 4441 or with any balamnced hand not containing 5+ diamonds. Some modify this to allow a 1D opening with 5+ or 4441.
With an unbalanced diamond approach, the minor openings are split into types. Balanced hands without a five-card major ae always opened 1C. Unbalanced hands with club anchor are always opened 1C. Unbalanced hands with a diamond anchor are opened 1D. This limits the 1D opening to unbalanced hands with a diamond anchor.
Within that approach, there are variations. Some are "purists," treating only hands with a stiff or void as "unbalanced hands," such that 6322 or 7222 hands with long diamonds are nonetheless opened 1C, or are rarely opened 1D, or are only opened 1D in 3rd/4th seat. Then, there's the 5422 problem. Some open 1D with all 5422 hands. Some only open 1D with 5422 if holding both minors. Some open 1D with 5422 unless specifically 2452.
Some unbalanced diamond people even decide what to do with these problem hands. Maybe long-diamond balanced hands are an easy-to-handle exception and therefore discretionary, whereas 5422 hands are more complicated, governed by honor spread, overall strength, or some other analysis.
And then there's the random people. A "random" minor person would always open an unbalanced hand in the anchor suit, but a balanced hand could be opened in either minor if both minors have at least three cards. A wildly random minor handler might even have clubs possibly short, or even either minor possibly short.
Situation specific issues also come up for many approaches. For example, there are debates between whether 1D...2C might be canape (either minor could be longer) or even IS canape (clubs always are equal or longer). There are debates (for those who don't use unbalanced diamond openings) as to which minor to open if balanced and 2344 or 3244.
Alternative minor openings (like Precision 2C, 2D for the minors, unusual 2NT opening, Schenken 3C opening) also might tailor what minor openings show.
Then, there's the Nebulous 1D, of course.
I have even seen (and played) that a 1D opening, if balanced, denied a 3-card major (could have one or both 4-card, but neither will be exactly three) and that a 1C opening, if balanced, promised at least one three-card major. Or, this tendency was implied.
Of course, you also have styles where balanced hands are split between 1C and 1D by strength. For instance, if a 1NT opening is Kamikazee (10-12, say), then 1C...1NT might show 13-15 or 18-19 but 1D...1NT showing 16-17. Something like that, in any number of permutations. Years ago, a few of us buried the Kamikazee into 1D, such that 1NT opening was 15-17, 1C...1NT was 12-14 or 18-19, and 1D...1NT was 8-11 (with at least three diamonds), balanced. (This was a ton of fun.) Or, there was a K-s variant of that (1NT was weak, 1D for kamikazee, 1C for 15+.)
Some artificial or canape systems have potentially wild minor openings, with either possible as the strong forcing opening, and with the other usually grabbing onto a hodge-podge of problem pattern hands. For example, in my own canape approach, 1D shows either a diamomnd-major canape (longer major) or one minor (either one -- never both).