Been shooting medium format for a while now. P30+ with H2. First starting shooting fashion, but now found myself in a gallery here in Paris and see a lot of doors opening with the use of a technical camera.
Is it best to buy the Hasselblad HC Tilt/Shift system? Should I buy a technical camera? Which One? Any recommendations would be great.
It's a broad question you are asking. You'll get better advice if you can help us understand more of your specific needs/wants.
Do you plan on shooting fashion with the technical camera or landscape/architecture/interior. While a standard tech camera (e.g. Cambo Wide RS, Arca Swiss RM3, Alpa STC) can be used for anything (I once shot infrared sports hand held with a tech camera - not for the feint hearted), it is generally best for landscape/architecture/interior. Several users on the board use tech cameras for handheld street shooting, and a few here and there use it for other styles of photography.
Perhaps you intend to use it for fashion, but just mean that you'd like to add movements to your repertoire of camera control. In that case I think an HTS is an ideal solution. It magnifies the image 1.5x and you lose some aperture, but you'd gain tilt-shift on all your existing lenses and maintain through-the-lens focusing and composition (pretty important for most fashion shooting styles).
If instead you're planning on branching out to landscape/architecture/interior or going to use the human form, but not in a static manner (lots of time to set up each shot, limited movement within the frame while shooting) then a true tech camera may well be a better tool. It provides the absolute best lenses, movements entirely in the rear on some models (better for stitching and for fine tuning carefully crafted compositions), large ranges of movements on some models, and the tactile feeling of shooting a more traditional/mechanical camera which some (including me) enjoy greatly.
One big gotchya here however is that you're using the only Phase/Mamiya-Leaf back which is strongly recommended NOT to be used with a tech camera. Your P30+ (also the non plus version) has strong/steep micro lenses which make it very hard for the sensor to see off-axis light. When using a wide lens on a tech camera, or when adding tilt/shift/swing to any lens you are throwing light at the sensor in an off-axis way. For most backs this creates a minor inconvenience (color cast which requires one calibration shot for any given lens/movement setup), but for the P30+ this often makes the shot unusable.
So if you want to go to a pure tech camera you'd need to upgrade your back to get much out of it. An IQ140 or P40+ would be the most natural progression but there are a dozen other possibilities (e.g. DM33, DM40, P65+, IQ160 etc etc) - you're using the only Phase/Mamiya-Leaf back which is so poorly suited for a tech camera. The P21/P21+ has a similar issue, but not as severe.
So tell us more. As much as you tell as about what you shoot, what you want to change, what you're likes/dislikes/priorities/budget are the better the advice you'll get from the forum!
Also once we know more about your needs/wants/priorities we can link you to a few threads with relevant discussions that have already occurred. This conversation has happened in various forms several times in the last few years.