I have to ask how long these to long post are..... 20'? With 6 bents and all splices(although there now seem fewer) that would be 12 post, each post having two halves for 24 pieces. Depending on the skill and tooling each could take 2-5 hours to cut. In splicing alone I can see 6-10,000 dollars in additional labor. It would also require more board feet of timber,as the short piece would require the length of the splice extra plus the dropped ends of each piece. This is decent enough justification to use long timber, let alone the structural issue it brings. I would throw some iron at it and bolt them if it came down to splices. A glued joint is going to require even more time to execute, you will need exceptional tooling and/or patients.

Also, with these splices think about the raising and how the slip of a bent would could effect this splice? Getting a bent into the air is not always a pleasant thing.

Source the correct length timber and have it shipped in.

Glad to hear J. Sobon had issues with too many splices in such a frame, Dave.