xs power; battery

I have two XS Power D3400 batteries that I've been running for the past two years. Recently my alternator went out which caused them to drain completely and sit in my truck dead for over a month. I recently took them out and charged them both up. It took 3 days for each one to charge above...

1. Product: XS Power XP3000 2. Specs: Product Description 12V BCI Group 31 AGM Battery, Max Amps 3,000A, Ah: 120, RC: 240 Weight Lbs. – 73 Weight Kgs. – 33 Length – 13 in Height – 8.65 in Width – 6.8 in MAX Amps – 3000 RC – 240min Ah – 120 M6 Terminal Hardware Included 2 Year...

Gonna be running a BC2000 and BC1100.4, Need helping picking a battery to go with my Yellow Top. I will eventually be upgrading the yellow top to a D3400 and getting a 270amp alternator. Looking to buy a XS power battery Thinking the D3100 unless a smaller battery could work im all for that...