I think the type of deathmatches should not be completely random. For example suppose there are 24 deathmatches that occurs in 24 hours. These 24 dms should be equally devided between all 8 types . ie. All types should get 3 dms during those 24 hours. The selection of typed would be random but as soon as any type completes its 3 dms quota there won't be any dm of dat type during that 24 hrs.
And if u can , provide the details of the numbers of dms left for all the types for that day. Start and end of the day will be decided according to gmt.
In short all dm types should get equal chances.