I like these forums cheers for the quick replies guys.

IanY, first attempt at metal lapping (after practicing on some scraps first), have figured a telescope mirror before though, but I cannot attest to my skills with metal unfortunately, so for best performance bowing is the way to go with the GT/GTX.

I would tend to agree with you aswell that there will more than likely be no outright winner. However, one factor that could decide it in the D-Tek's favour (for me) is if it offers comparable (+/- 1 or 2 deg) performance to the GTX bowed then it would seem a clear choice as it avoids the required bowing (easy, hassle or otherwise) of the GTX.

nikhsub1, I think I understand the reasoning behind the bowing better now, makes perfect sense. cheers.

And phelan1777, thanks for the welcome