There are many ways to check circulation,simple clinical ways or more complex radiographic reports.
The simplest is to feel with your two fingers for pulse just like you check the radial pulse looking for consistency or regularity and most importantly weakness in flow. weakness, felt thinly(described by academicians as thready pulsations) or not at all may suggest a compromise more proximally.you should not press down on the artery as that can give you a false negative result.having said that, the aterial system is marvellous in arteriogenesis(creating anastomosis) therefore if one feels normal (pulse feels adequate)does not mean all is well.

you could improvise with a doppler ultrasound machine to hear the flow.strong flow will be loud and sound like a dog barking(sometimes you can hear a little high frequency dog bark). The most important thing is to hear it and trust me when you do compared to a compromised circulatory situation you will know the difference.Place the doppler against the flow of the artery, trial and error may be needed sometimes to hear the flow.

other ways are to measure ankle/brachial ratios and I forget what the normal ranges are right now. This is perhaps the most objective you could get in a clinical situation. its just measuring the ratio of pedal pulses compared to brachial artery pulse.

finally, good old radio graphs are handy in showing you were a compromise is but you need a marker of a sort to be injected in the artery to outine the course of the circulatory system. Excessive opacities in any aterial segment compared to the contralateral part suggests a compromise.

Cyclists and rowers often get compromises without knowing because they bend a lot closing down the iliac arteries.they only notice when they start to run.

My reasoning is this: bilateral symptoms happening at the same time must have a more central or proximal cause. unlike unilateral problems that could be either. I am not saying you cant have bilateral problems that have independent unilateral causes, you could but if I was to see a case like that, what I would hold priority is a hypothesis that links both symptoms; I think that way because the body is a chain of little blocks.

I reckon that ruling out circulatory problems should be priority in sports medicine especially in unremitting cases. if it was standard practice to do that, I think it would be a lot better.

bilateral shin splints happening at the same time everytime in the same situation must have a link.It is harder to reason that one out, if that is the case, I would be happy to know why.

your suggestions are very valid because you considered many factors that could link both calf symptoms together e.g training shoes etc

I hope I was of some assistance