a capped semi, or psp 2/3 shot is ok. Under no circumstances can your marker shoot faster than 12.5, or fire more than 4 shots per pull (and only after 3 semi shots). All of this is addresed in section 9.3.6 of the PSP rulebook. You just don't know how to read it.
how long you have between points is dependent on the schedule, as well as how long points take. the rule book will give a concrete time because they vary from team to team. In the PSP they give you time to air/pod. Though there an no back to back games. in the even that there is, plan 2 minutes since this is an affiliate series, Id bet this is the same. for race to 2, plan 3-4 minutes, depending on how many games in between yours.
that was the phoenix D3R22 sched. should give you an approximation of how things work. note that you play each other team in succession, not back to back with others in between. IE you're team A her is your sched:
B,B,B, C,C,C, D,D,D, E,E,E.
All of that is in Section 4.1