I allready did that step and it should now be dry for removal being pined to my working board. I spliced the 1/4" balsa sticks by cutting at a 45 degree angle.
Rate1 ..you will have lost a little strength continuity across a 45 deg splice...maybe add a short (maybe 1" long) buttstrap across your splice..you can chamfer the ends of this splice (45 deg!?!!?) which will reduce weight and also help transfer any load back into the adjacent parts of the main longeron. I also have the xacto "mitre" jig but didn't use it since 45 deg leaves far too insufficient joint area for a splice ...save that for making gussets and making triangular corner joints. Glue these buttstraps to the corner between the side skins and the longerons.
Cheers