Hi Martin, welcome
Low drain vs. high drain:
"High drain" is better for watches with functions that demand momentary high current (LED watches, alaram, backlight). It has less internal resistance, especially at low temperatures - i.e. the voltage will not "sag" so much when high current is demanded. On the dwonside, it has 5-10% less rated capacity than "low drain".
"Low drain" has slightly higher capacity but cannot deliver high currents due to higher internal resistance, especially at low temperatures. Their "shelf life" is a bit better.
Because a watch on the wrist rarely sees temperatures below 20°C when used, low/high drain does not make much difference.
Anyway, I'd use low drain only for analog or LCD wthout alarm/backlight. Just to be sure .
For your watch:
2.1mm high SR1120W = 391 (high drain)
2.1mm high SR1120SW = 381 (low drain)
3.05mm high SR1130W = 389 (high drain)
3.05mm high SR1130SW = 390 (low drain)
If the 3.05mm fit in, use them. They have double capacity.
For battery charts see this thread: http://dwf.nu/viewtopic.php?t=2583