Based on whatever time limitation you have aim to get to a specific numbers of completed sets. Could be 3, 5, 7 etc.
Use a moderate rate, don't worry about going to heavy the first few times out. (I currently stick with 2 plates right now as the surface I sled on has a lot of resistance)
After each workout assess how well your body has recovered. Do you feel fresh the morning after? At the end of the week are you worn out? If the answer is no, up the weight or the number of sets completed. I would stick with upping the sets before manipulating how much weight you have on the sled.
If the answer is no, reassess your nutrition, how much sleep you're getting each night and maybe look at decreasing number of sets or weight on the sled.
Once you've reached your target amount of sets you can start to progressively increase the weight weekly over time. For Lower body Sledding I would think 20-30 lbs increments would be doable. For Upper body Sledding 10-20 should be just about right.
There are an infinite amount of ways to assess how much weight to use this is just an example of what I'm doing.
If you need anymore help feel free to PM me.
Ps. Here is a copy and paste of CT's original article
The Simple Rule for Adding Volume
The simple rule is to use metabolic fatigue as a guideline, and never train to the point where you feel like you have nothing left in the tank, energy-wise.
Here's a good test: 15 minutes after your last set of eccentric-less training for legs, you should feel like you want to do more. I'm not suggesting you actually do more; just take note of how you feel, and use that as a gauge to determine when you've overdone it.