I dun really remember exact figure leh, but first time offender, what I remember for within my powers.... is 1 day DB for every 2 days AWOL, that is JDO summary trial for those who awol a few days one. This one is court martial case, so might be different case. Court martial sentencing usually look at past cases, not sure if public can access court martial similar past cases, with some minor changes for different cases.
As above, this is court martial case, so first need to wait for court martial date, he will be in DB on close arrest until then. Sentence, might or might not start with his first day in custody, depending on how long the sentence also (if few years, few days difference wont make a significant difference... if few weeks, a few days will make some difference).
Home visit will be most likely made by defending officer. This is just to understand and verify his family conditions for the mitigation plea. Do note that defending officer is just another NSF officer who cannot do much for him except help plead guilty and read out the mitigation plea, the prosecution is a civilian lawyer, NSF 2LT wont stand any chance arguing with a trained lawyer. If my memory is right, sentence will be about 2 years, with possibility of 1/3 discount for good behaviour, so about 16 months after discount.
For visitation, I can't remember if can do so now, but definitely can do so after sentencing. Unit should inform them of court martial date, and you can go for the hearing, like normal subordinate court. Court martial is at Kranji camp, DB just behind that. I'm not really sure if gf not allowed, but I think got limit, like 2 person per visit, 1 visit per week. My unit last time go ppl in DB also, I remembered the gf got go visit or at least the detainee (habitual awolee, like 5th time already) said so.
Editted: yeah, close arrest is the word... me forgot the exact term, didnt read last few posts before posting.