Hi musiclava,
The sound level can be controlled thro the software also, and can be optimised using normalise function of the software. The whole exercise can be meaningful only if the LPs have been maintained well and have less surface noise(clicks and cracks). Clicks can be easily edited but the continuous crack noise will be annoying and if filter is applied beyond a limit, may eat a portion of the music. Anyway the LPs have to be physically cleaned prior to sampling. Also ensure that the rpm of the TT is perfect, no rumble noise is present and the cartridge used is of good audiophile quality like SHURE MX97E or at least a Audio-Technica AT-91. Pl ensure that the sound is captured thro a good sound card, which will be better than the onboard sound.
I am not pessimistic about the whole process but trying to share my experience of converting LPs to CDs, and to hint at certain flaw that may crop up.
As for the 78 rpm LPs there is a special SHURE cartridge for the same.
Hope this helps.
N.Murali