Thanks everyone for the help!
Demoing a reserve would be tough right now as this is my first rig and I don't have a reserve already but it is good to know that they will send one out to try out as a main, I didn't think that was an option.
The recommended reserve is a PD 143 (see below for options listed on the mirage site for my model). But I would like to go with the safest option and from what I can tell larger generally equals safer. Note that I am quite new to the sport, 1 year 100 jumps, so have only jumped rental gear up until this point and have a lot to learn about all the gear. I mentioned the Smart 150 only because it is the only used one I can find at the moment which would save me $800-900.
If it is being packed by an experienced rigger, what are the downsides to getting one that is a tight fit?
Pack Volume 300cu.in.
Aerodyne Research Smart 135 – Soft
Aerodyne Research Smart 150
Flight Concepts 145 Cricket
Icarus Reserve 149
Icarus Nano 176 – Firm, No Larger
PD Reserve 143 – Recommended
PD Optimum 160
PD Reserve 160 – Firm
Precision Aerodynamics R-Max 148