If space is at a premium I would consider the Group 31 "HT" lifeline. That would give you more margin with rainy winter cold fronts. The new alternator working will charge at peak level, for more time. A one hour drive with a 100-amp hour gain from the alternator is nothing to sneeze at.

Specifications
Volts
12
Length In (mm)
13.46 (341.9)
Width In (mm)
6.77 (172)
Height In (mm)
11.95 (303.5)
Weight LB (kg)
96 (43.5)
Cold Cranking Amps
68F
1000
32F
850
0F
700
Rated Cap. Amps Hours @ 20hr Rate
150
Minutes of Discharge
25 Amps
315
15 Amps
555
8 Amps
1120
Shop located in El Cajon near Santee. Hours Mon-Fri 9am to 4:30pm Sat 9am-2pm Address 1985 Friendship Dr. Suite H El Cajon, CA. 92020 (map) Shop Phone (619) 448-5323 Text (619) 315-5604 SanDiegoBattery@gmail.com