Tempo time targets

I was hoping to get some advice on what times to shoot for on low tempo days in the high/low system. As a decathlete, Ive been running so far mostly 100s and 200s at 60-75% of my prs from last season. I want to move up to some 400s,500s,600s to prepare for the 1000m in the indoor hep. In the Clyde Hart fall prep I’ve read, he advises to base your tempo on goal times for the next season instead of past season bests. In the 400m I was in the 52-53 second range during 2015 and want to run sub 51 in 2016. So I’m unsure of what style to program.
Also how would I set training time goals for 600m and 500m reps if I’ve never ran them?

I would set the training goals for 500s and 600s based on your 1000m goal. If you want to run the 1000m in 3min, for example, you could do 3x500m in 1:30m with short rest. This is very different from extensive tempo though. Extensive tempo is active recovery, while this would be a fairly intense middle distance training session.

There is no much of prep for 1000m in decathlon/heptathlon, it comes out of your special end sessions and possibly one tempo session, or if you can train twice a day two sessions a week, there is too much to cover in other events, points for 1000/1500m are not that massive in the first place to worry about it, comparing to hurdles or 100 and long jump.

To cover all technical events including 400m and 1500m decathletes train most of the time from long to short.
All the events are quite taxing except 1500m. Long to short in my opinion allows decathlete to spend more time in general prep which is essential to prepare for technical events (which are quite taxing anyway) so by using longer runs they have to balance total stress on the CNS.

Dvorak and Sebrle in their prep were doing stuff like:
Monday: 4x20, 3x150/21, 2x200/28, 3x600/1.50, 3x100/12
Wednesday: 2x60/7.2, 3x300/47, 100/11.8, 2x300/44
Saturday:Fartlek sled/bounding/running/walking

So there is a lot of running there, lots of bounding, weights and medball.
They were performing (first comps) quite late in the indoor season around end of Jan.