Just thought I would point out that we have had a discussion of Imperial sub-light propulsion here, including some forays into modelling it with GURPS, that you might find helpful.
Thanks mate, that actually clarifies things very well!!!

If you're talking about the Venturer, please note that the statistics posted were reflective of a Golden/Dark Age of Technology (G/DAoT)
That too clarifies things quite a bit...
The whole TL^ thing is a tad on the annoying side, but not half as annoying as the reduction in the TL scale from TL 16 (etc.) down to TL 13.
Quite

Heck we don't need to use the ^ if we don't want to... essentially anything
Adeptus Mechanicum is ^

In essence, anything TL10 or above is superscience, and includes artificial gravity, contragravs, warp-drives, forcefields, and all forms of highly efficient reaction drives (antimatter). TL12 would include truly exotic items such as teleporation devices and total conversion and reactionless drives.
As before, to get values acceptable to the people on the forum you have to dramatically increase the delta-v of fusion drives to allow for the accelerations required to get people to the "warp zone," as we're currently defining it, within the month or two requested.
I see what you mean... I'll try to run some numbers with the current TL9-10 systems and see what I come-up with. The
Plasma Reaction Engine (shown earlier in the post) was my solution to the problem earlier last year, and I've used it in the design of the Horripilar.