I've been using it on a tripod so far as I don't have a rail and I'm pretty shaky, but I'll give it a go without.
FWIW, and IMO .... And sorry for the long post, but ... there is a practical suggestion at the end.
(And the less powerful 150 makes all of this a bit easier BTW).
Indoors, when I am working with flat surfaces (the floor for the tripod, and a table or similar for the subject), and I can take my time adjusting everything, then I find I can can use the tripod in the "normal" way - set up the shot, put on the self-timer, press the button and wait for the camera to settle down before the shot is taken.
Outdoors, which is where I do almost all my macro work, I often find it difficult to use a tripod in that way.
To get a really sharp picture with the 250 and make the most of the limited DOF you need to get the distance right, and getting that degree of exactness out of a tripod can be tricky with uneven ground and subjects in odd positions and at odd angles. For example, depending on the way the tripod works, it may be difficult to make very precise adjustments, and once you have done the adjustment, focused and pressed the shutter button and let go, the tripod may "relax" into a slightly different position, just enough to spoil things.
Timing can also be an issue with using the self-timer out of doors. The slightest puff of wind can ruin things, and around here at least it is rare to get a day when the air is completely still. I often have wait for a moment when the subject is momentarily still to take the shot and the self-timer doesn't give me enough control for this.
Another timing issue is that when the light is strong enough to use a fast shutter speed (or you use flash as the main light source) you can "freeze" the subject, and avoid blurring from both your hand movements and movement of the subject. However, because the distance to the subject is so important with the 250, if the subject is moving at all it can keep moving in and out of the "good focus" distance. Also, unless your camera can track fine movements of a macro subject very fast (like the Canon 7D), slight movements of the subject will alter where the DOF falls, which can make or break a macro image. This is all another reason for wanting to have complete control over exactly when the photo is taken - when the subject is as still, or slow moving, as possible.
Another approach I use, especially when the subject is moving, is to take a burst of shots (or actually, a number of bursts) in the hope of getting one where everything falls into place.
Because of all this I keep my hands on the camera the whole time so I can make fine adjustments to distance and choose exactly when to press the shutter button, and how long a burst to use. But there is a snag ... my hands shake, quite a lot, and this makes it very difficult (almost impossible) for me to get good control of camera to subject distance while also getting the compositional framing I want.
So, I use a tripod to damp the camera movement. I (usually) keep my hands on the camera, and I don't use the self-timer. But having the camera supported keeps the movements small and centred around a fairly fixed point. This is enough to make it practical for me to frame shots nicely while keeping the distance within acceptable bounds.
As it happens I now use a heavy, complicated tripod with an arm that goes out sideways, up, down etc at any angle, the arm coming off a central column that can go up as normal, or down towards the ground. And I use a focus rail too (in a rather crude fashion).
However, before I got this tripod I used an ordinary one. What I did, and what you might like to try, is to shorten one of the legs to its minimum length, and just use two of the legs - a "bipod". Adjust the height of the legs to suit the height of the subject off the ground. Place the two legs (if you can) on an imaginary line at right angles to a line between the camera and the subject. You can now rock the camera so that its distance to the subject changes, but it doesn't move sideways. It makes getting (and keeping) the distance right and framing the shot much easier (for me) than trying to do it with no support.
