damn straight.
the relationship between rim size, manufacturer's nominal width and safety is unclear at best. semi slick manufacturers sneak very very generous fits into their sizes to give their tyres an advantage.
follow what the manufacturer says for that tyre. If you are not sure ring a distributor.
but back to your first question (slicks vs semis)......do you think the teams selling them are idiots?!? they are being sold because they are past their best. compare a second hand slick to a second semi, not a new one. there is every chance a second hand slick will be slower than a new or near new semi.
BTW I am selling some second hand slicks. They are very cheap (30% of new price), because they are beyond their best.
Fine if you understand that and know what you are getting - they will do the job fine and are cheaper than chewing up road tyres for basic practice. But you will not get the best out of your car on them