I can buy these base fittings at 90deg for the stanchion and 45deg for the fore and aft and lateral struts to hold each side stern pushpit stanchion vertical tube which goes into the 90deg base fastened to the deck.

chain.com.au/collections/rail-fittings-stainless-steel/products/rail-fittings-rail-base-round-45-degree

I can't buy a 3 way tee at 45deg - need 4 - 2 on each stanchion.

chain.com.au/products/rail-fittings-3-way-tee-60-degree?srsltid=AfmBOop7Frmx3wN7YxmV7e7euD0Ss11iWIxw2yGSfVTzVdznQ7vSpTOg

Does anyone know where I can buy such a tee. IMHO it doesn't make sense to sell a 45deg base yet not a matching 45deg tee.

Maybe I will have to make the stanchion to 45deg struts welded joints. I can't weld 1.6mm diameter 25.4mm od tube - thought I could - so its going to cost an arm and a leg.

Thanks in advance.

Great thanks K. Yes bending the 45deg stanchion to conform to the 60deg T would be possible. Don't need to go down the wedge packer route as those bases are available in 30, 45, 60 and 90deg. I will investigate the 15deg bend option - probably the solution as per Ogis below - should be a lot less spendy than welding and a lot less effort in me grinding out the 45deg fit in the 45 deg stanchion to vertical stanchion for the welded joint.

ogis.com.au/services-capabilities/pipe-and-tube-bending-and-rolling/