Stamps look decent. If you are near a library, see if you can check out a Scott Catalog for the countries you want to check. It will take some research, but could be interesting for you. Advice on stamp club is a good suggestion. Be patient.
There are a few better issues here -- but beware, your King George V ten-shilling value, at the bottom of the Solomon Islands page, has what looks like may be a fiscal cancel (the stamp is much more valuable postally used than fiscally used.)
The North Borneo issues all have remainder cancels except one: after the stamps became invalid and were withdrawn, they were given that oval bar cancel and sold in bulk to the stamp market. The one North Borneo with the non-remainder cancel also looks like a fiscal use (which is too bad, postally used North Borneo are quite scarce.)
The Samoan surcharges come with a number of perforation varieties, if you have a perf gauge you can determine which you have.