You do not have to have a hose on the solenoid. You will have to have the solenoid harness connector plugged in or you may get a code. I think that circuit has to have some resistance for the computer to read. As far as the hose goes you can run it straight from the compressor to the wastegate actuator but you may lose some computer/chip control benefits but many people do and just adjust the boost with a manual boost control or by adjusting the actuator rod length.
If you want to keep the solenoid you need the correct metered y, a regular vacuum tee won't work correctly. The leg of the y with the restrictor in it goes to the compressor. The short hose goes to the wastegate actuator and the long hose goes to the solenoid. The hoses are one size for most of it, 7/32" I think, but it is a smaller nipple on the solenoid so you will need an adapter and a short piece of hose. The hose goes on the one on the outside, nearest the fender. The y is the critical part. If you have it then the rest can be replaced with parts store stuff. If you don't, the entire hose assembly is available from many of our vendors. You can find many discussions on the solenoid if you do a search and if you need an illustration there is one on gnttypes.org. in the tech section.
