1) Not a big problem, you just write down on a sheet a table like this:Elyoukey wrote: several issues :
1-there is no block dice so you may need a hash grid (1=>skull 2=>push etc...)
2-one can fake the layout of the site and make his own rolling code.
1= skull;
2= both down;
3= push;
4= push;
5= push/pow;
6= pow.
Anyway, you made a fancy app, so no need to use a conversion table from d6 to block dice

2) You can easily check if the site is fake (you don't even need a laptop, today even mobile phones can browse the internet, moreover, if you share the site's dice rolls there would be no benefit from a fake site).
About rolling "real cube" dice: yes it's a bit weird but we do it every time we play online Blood Bowl.
Since RNG dice results are more evenly distributed than "real cube" dice using a RNG is a wiser choice.