How does a solid roller cam act vs solid flat tappet

Hey there fabo friends, hopefully I'm going to ask this question correctly. Currently I'm still in the build process of my 471. The dude who is helping me out with my build really really wants me to buy a solid roller for my engine. However I already had planned out & purchased most of my parts around what my plan was. The cam I have now (still in the box & tube) is a howards cam, solid flat tappet with edm upgrade lifters & the proper springs for the required pressures. Besides the near $1800.00 to upgrade to a roller & the reduction of friction + the valves opening & closing faster, how would I chose basing on duration @ .050 ? Is a 260-264 @.050 solid flat like I have what I should shoot for in a solid roller or do the 2 cams act different.
I suppose I should call howards & ask them what the intake closing point is on the 2 cams I have in mind the one I really like has 258 or so intake 268 exhaust & .640 lift.
I don't want to over cam obviously & my compression numbers I can manipulate a little between 11.2 & 11.5.
Hopefully someone gets what I'm trying to ask. Thanks guys !