Please don't add two angels. First of all, unless they are a mated pair, the most dominant fish will kill the other one; angels need to be kept as single fish, mated pairs or in groups of 6+. Second, it's a bad idea to try keeping angels in a tank with tiger barbs; even though you've got group of tigers, the slow swimming, long-finned angel will be too much temptation and the barbs will bully, nip or otherwise harrass it.
You could add another 4 tigers if you get rid of the black widows,
The problem with your tank is that it's very short and deep. I know people often go on about '1 inch of fish per gallon' (I do myself!) but the real limiting factor is surface area; your tank can't be as heavily stocked as one that is longer and shallower.