The whole ghost thing was explained to be the result of AIs. Which is a bit dubious, but seeing as Tex was a ghost it pretty much confirms that she is an AI. Which is why a well-equipped but SCPless Clef's subliminal messages won't work, this stuff is pretty specific and her hardware is completely different and her software should be sufficiently different that it has no effect, and without a similar AI to experiment on that isn't going to change...
http://scp-wiki.wikidot.com/scp-127 Automatic piston, 60 rounds, fires teeth... Almost no potential to overcome armour, so once again we are looking at something that is only effective in melee...
http://scp-wiki.wikidot.com/scp-244 More lethal to Clef than Tex, takes FAR too long, massively reduced effectiveness in sunny-outdoor environment, which would be consistent with the battlefield's dubious description. Probably call it night time as both competitors can be assumed to have vision enhancements so it would be a less biased event if this useless apparatus was involved...
http://scp-wiki.wikidot.com/scp-063 would destroy all other Equipment Clef carried, and is once again a melee effect.
Other than an increase in melee effectiveness and a severely dubious potential for concealment that cannot actually be exploited. None of these would be preferable to standard military equipment.
Clef with usual equipment: Labcoat versus gun, Tex wins.
Clef with anti-vehicle rifle, semi-automatic pistol, stun grenades, vision enhancements, and subliminals: Depends upon quality of sniper positions and ability to attain them, in a medium and/or close-ranged battle Tex will have the advantages of speed and armour, and will almost certainly prevail, at extreme distances, it depends if Tex is allowed to have her sniper rifle, with it, fair fight, though clef may be more patient, Without it... In combat situations Tex is a pretty difficult target...
With the above SCPs: Naked versus gun, Tex wins unless they start at point-blank range, in which case the toothbrush will instantly annihilate Tex...
Clef in 'break my neck and throw me around' mode: Disqualified due to invulnerability.
Clef post
http://scp-wiki.wikidot.com/all-they-want-is-the-blood: disqualified due to lack of vital functions...
Until someone actually provides an argument in Clef's favour, rather than just talking about how awesome he is, I don't see Clef winning this, I don't even see a contest, which is why it will come down to a comical refrain and involve Clef losing the ability to reproduce...