Hi Vince, sorry for the delay; life.
ref 1> I would prefer to have level, XP, and bonus to be tracked and shown separately per class as your image below indicates. Looks great to me.
ref 2> I intend to track HP rolled per level (per class) for our characters for the reason you stated, and was going to use the Notes section at the bottom of the sheet. If there were dedicated fields set aside for this, that would be great, but I wouldn't demand it.
ref 3> page 32 of the PHB indicates rolling the new level die and dividing by either 2 or 3 depending on how many classes total there are. The text fails to reference the addition of the CON bonus per die, and does not deal with the obvious staggering of level progression since each class has their own XP milestones. i.e. an MU//Thief moving from 1st to 2nd level will hit the thief milestone first, so they will roll their second d6 without having an commensurate d4 roll for the MU class. If we assume a 15 CON and max values for levels 1//1 (4+1, and 6+1 = 5 + 7 = 12 /2 = 6 HP), when going to 2nd level Thief rolls a 4 (+1 = 5 /2 = 2.5 additional HP) for a total of 8 HP* at levels 1//2. It is only slightly more complicated with triple-class .333 remainders after division.
* I have always rounded down in cases like these and waited for the 2nd level of the other class to make adjustments. i.e. when the 1//2 MU//Thief reaches their 2nd MU level they roll a 2 (+1 = 3 /2 = 1.5 additional HP). Having truncated (but not discarded) the .5 HP from the previous advance, they now increase by 2 HP instead of 1, for a new total of 10 HP at levels 2//2.
If the sheet were to keep track of totals by class, assuming max at lvl 1, let's try (at levels 1//1//1)
Fighter 11 (10+1)
Magic-User 5 (4+1)
Thief 7 (6+1)
changing to (at levels 1//1//2)
Fighter 11 (10+1)
Magic User 5 (4+1)
Thief 12 (6+1 + 4+1)
changing to (at levels 2//1//2)
Fighter 18 (10+1 + 6+1)
Magic-User 5 (4+1)
Thief 12 (6+1 + 4+1)
changing to (at levels 2//2//2)
Fighter 18 (10+1, 6+1)
Magic-User 8 (4+1 + 2+1))
Thief 12 (6+1 + 4+1)
A simple sum divided by the number of active classes (truncating the remainder) would yield 7(.666), 9(.333), 11(.666), and 12(.666) HP respectively. This is how I understand multi-class HP was intended to be implemented. Please correct me if I've had it wrong all these years.
Chris
vÍnce said:
Starting to flesh out some sheet updates...
1. Is it beneficial to track HD, HP, and XP per class? Perhaps something like this?

2. Should HP be tracked per level as well? (in case of level drain or similar)
3. I'm also torn on what should actually be calculated by the 1e sheet? Focusing on HP specifically for the moment; I could include additional column(s) with a running total of "rolled HP" + (CON bonus * Class_Level) and display a "Total Class HP" calculated by the sheet. Current and Max HP would still be shown at the top of the sheet. Again, hitpoints_max could be calculated by the sheet and would take into account multi-class characters, but the math would need to be done BTB. I know many people house-rule multi-class hp calc.
Thoughts/Suggestions?
Thanks