[49Stude63]

You could do the 12 with a 15uf here is a link http://www.justradios.com/capacitors.html and use a 20uf for the 16. I would just use all 630V since there is not a lot of price difference. With the 1250 your could go 1200 or 1350pf and the 5300 you may have to go with a 5000 + the closest for the total. But if you figure 10% then 5000 + 10% would be 5500pf so if the 5350 was 10% on the low side it would be under 5000pf, tough call on that one.