Help with clrmame to rollback/rebuild or whatever works...

[abispac]

So heres my situation, i have a selection of mame 145 roms, mostly classics, about 130 games nothing ealse, they all work just fine in mame but im using an old pc and the games just strugle to work as they intent to work, so im using mame 105 now most games work just fine, but i need to rollback some games in order for them to work with mame 105. I have tried to just fix them with the rollback roms package i got from a pleasure site. How i did this, well i just set the mame 105 in clrmamepro to create a datfile, add roms path, add rollback as add path and the doa scan with the fix option selected. But that dosnt seem to work as romsets such as kof2003 give a missing file error. I tried rebuild them but that just make a mess and creates lots of unfinished romsets and erases alot of them too. So im kind a stuck here, as i dont have 40gb to download a whole 145 set just to rollback to 105. Hope someone here can spare a trick on how to acomplish what i want. thanks for any help.