Not only is the 102" whip impractical it is really not a good antenna.
The 4' fiberglass antennas are good performers no matter which manufacturer you buy,
Most are top loaded and radiate from the top first so you will get a higher signal.
Most are relatively easy to tune and yes you need to tune your antennas for lowest SWR no matter what people tell you or what the packaging tells you.
My choice is Wilson! they make one of the highest quality CB antennas out there. They have fiberglass and the base loaded with long metal whip and also the original Trucker Antenna with different lower rod lengths to accommodate most mounting locations.
Remember all mobile antennas are a compromise, a full wave length for a CB is 36' so that would be very impractical on any vehicle.
Most mobile antennas have coils either in the base or along the length to make up for the short length.
Base loaded antennas need to have the loaded base above the roof line to effectively radiate a signal.
Remember one thing the higher the better for a CB antenna so the roof is the best place, centered on the vehicle metal mass.