You have a 1.4 Xbox, so the TSOP is 256k, so you need a 256k BIOS. Your choices are iND-BIOS.5003 (although I can't find a 5003 VGA that isn't BFM, so you might have to use 5001, or patch your own 5003 VGA version), X2.4981, or Evox M8+, and all support LBA48. You can't use X2.5035 on your TSOP, because it's 512k.
Possibly the easiest way to test your system is to try the BIOSes in Frostys_BFM_VGA_BIOS_Pack.rar, using PBL to load them (Frosty's BFM VGA BIOS pack contains PBL and instructions). Once you have it working and have found a BIOS that meets your needs you can flash the non-BFM version of your preferred VGA BIOS to your TSOP. (DON'T flash the BFM version you have been testing with because it will brick your Xbox.) FYI, you have to boot with the softmod in order to flash the TSOP (you can't boot from the X2.6 chip then flash the TSOP), and you should be able to flash with Evox.
If you want to switch between VGA and standard TV you could flash a standard BIOS, and just continue to launch the BFM VGA BIOS every time you want to use VGA. Alternatively you could do it the other way round - flash a VGA BIOS then use PBL to load a standard BFM BIOS - it depends on which you use most. The final option is to leave the softmod in place, set up for either VGA or TV (depending on which you use most), and use PBL to launch the BIOS for the other set up. You don't get control of the boot sequence, but it avoids soldering.
Of your options, iND-BIOS gives you the most control over the startup sequence of the Xbox, and you can make all the changes to the ind-bios.cfg file without reflashing, so I'd start there.
