The Midwest Industries T1/T2 Red Dot Optic Mount lower 1/3 model will work with the Holosun 403B. The Holosun 403B uses the Aimpoint Micro footprint.
The Vortex Sparc AR uses the Aimpoint footprint. So this Midwest Industries T1/T2 Red Dot Optic Mount will work with the Vortex Sparc AR.
Midwest Industries does not provide a measurement from the top of the rail to the top of the mount. If you wanted to find that information, I would recommend reaching out to Midwest Industries directly.
Yes it should work.
Yes, this should be compatible.
Yes, these should all work with the the Sig Romeo4H.
Unfortunately, none of these are going to work with the Sig Romeo5XDR. According to Sig, the AAA battery versions of the Romeo 5 are not compatible with the T1/T2 mount because of dimensional differences in the base.
Unfortunately, none of these are going to work with the Sig Romeo5XDR. According to Sig, the AAA battery versions of the Romeo 5 are not compatible with the T1/T2 mount because of dimensional differences in the base.