Hello,
Thank you for your feedback. To be honest I had the same idea when I saw those two spacers inside of packaging. First smaller one is usable for default position of the support bracket. The other longer spacer would give me the space I am missing. Unfortunately it seems that designers in TT forgot to include second position for the support bracket in case - because there is no possibility to assemble the complete support bracket higher than is the default. If I decide to put the second longer spacer in place, I just rise the bracket on one side what makes no sense at all. The Core P5 vertical bracket seems to be 1 piece. In my case this bracket is made from 2 parts - standard back VGA bracket + the supporting one inside the case (where the spacer is placed).
Regarding the riser cable - I bought TT riser cable in order to avoid assembly issues. LOL.
If you check the picture in here, it is easy to notice that there is missing second higher slot for the support bracket. It is either this position, or the same position with one edge higher than the other ones (I wonder who thinks that is a good idea), or you have no support bracket at all. Case manual does not mention anything about two options for the support bracket assembly.
Is there a compatibility overview for TT cases? Such basic thing should be available in order to avoid these kinds of situations.... Maybe the case is not even RTX compatible, but I guess only TT knows.