as many noted here.. there are intensifiers, i have the fotospeed and works good in those rare cases when it happens(not corrct exposure on 35mm). the selenium is a great thing generally. i always use it. but it will not add details (nothing will add it actually). generally all those methods should be taken as fine tuners and not as saviers of what had not been done.
the paper is also very importent. agfa mcc is not the best choice in those cases of thin negative. ilford, kentmere oriental is much better.
what i usually do in those cases is printing on the hardest grade and then maeking the timing of exposure developer and finally putting the developped paper in the deluted selenium for long time (15 +min) it works good with bromide papers since they will not change the heugh.
but the best way is lith print if u are femiliar with it. thiner negatives are great with the lith but again u have to experimant it to find te best exposure/developing combination.
again if u follow all those intesification methods from the film to the paper itself while reducing the enlarging magnification u can save your negative and even find some of those stategies to give a very aesthetic photos.