Size of torpedoes

[Captain Seafort]

The "standard" Glikar'ma had a maximum warp at 7,2 - to slow to imitate faster ships.

Not necessarily - just because ships are capable of travelling faster doesn't mean they always do. The E-D usually puttered about at Warp 6, despite being capable of Warp 9+. The only potential issue would be that the Glikar'ma would be pushing her engines much harder than the ship it was imitating to achieve that speed, which might be detectable. This might be rationalised by simulating damage to the ship.

[McAvoy]

Well one thing we can say is that whilst the torpedo launch tubes on the front of the E-refit are oblong holes about 1.4 x 0.6 metres, the one on the front of the K'T'Inga is a round hole about 4.5 metres across. So Klingon torps may well be significantly larger.

Which does make some sense. I think we've come to an agreement many times here that the klingons are less advanced than the Federation, but managed to be a threat by specializing in warfare, building rugged and tough, and using brute force in their weapons. So them having a bigger torpedo makes sense, they need the extra big warhead.

Whilst non canon, many of the TOS novels made the comment that Klingon ships significantly outgunned their Federation counterparts, whilst Federation ships had far stronger shielding designed to take those kinds of hits. It does fit the mentality of both sides, too.

I always liked that idea myself.

[Chadic Garou]

Well, I believe I've solved the problem: Officially the Glikar'ma Q is a school vessel and a school vessel don't need an original romulan/klingon/ferengian torpedo. So we had only to simulate this. And a torpedo should be too fast to see it with your own eyes before impact - a holographic device isn't necessary. We only need a device which simulates the driving unit. No sorrows about the length of an "alien" torpedo.
But if we would play a dirty game we also don't need an original alien torpedo. We need a device which had the power of the original driving unit and an original warhead. After the explosion the torpedo should be totally destroyed - no debris no guilty.