Yes, the romeo 5 will fit and work.
This riser is made to accept any standard "micro" red dot and clones like the T2 or holosun 403 series.
It will not, the mount is made for the aimpoint micro series.
This riser is made to accept any standard "micro" red dot and clones like the T2 or holosun 403 series.
Yes, it will, but please be aware that mounting the Sparc AR on this is going to place your red dot at well over 3" above whatever you are mounting too. It's not a recommended set up.
Yes, the Unity Tactical FAST Micro Mount accepts all Micro footprint optics, and since the Holosun ARO-GD2 uses the Aimpoint Micro (T2) footprint, it is compatible with this mount.
Yes, the Unity Tactical FAST Micro Mount is compatible with the Sig Sauer Romeo-MSR Gen II, since it uses the Aimpoint T1/Micro footprint that this mount accepts.
Yes, the Unity Tactical FAST Micro Mount is built to accept all Micro Footprint optics, which includes the Aimpoint T2.
No, the Holosun SCRS uses a 509T footprint, which is different from the Aimpoint Micro footprint this mount accepts, so it will not fit directly on the FAST Micro Mount.
Yes, the Holosun HS503 is compatible with the Unity Tactical FAST Micro Mount.